# Top 50 Mobile Angel Investors in Germany in June 2026

## Thomas Madsen-Mygdal
- Type: Angel
- Location: Copenhagen, Hovedstaden, Denmark
- Relevant deals: 5
- Stages: Angel, Seed, Pre-Seed
- Focus: Computer, Software, Collaboration

Thomas Madsen-Mygdal is a Danish designer, entrepreneur and activist behind companies like Mondo, 23, Podio and the reboot festival.

## Ralf Reichert
- Type: Angel
- Location: Cologne, Nordrhein-Westfalen, Germany
- Relevant deals: 5
- Stages: Seed, Pre-Seed, Series A
- Focus: Education, Video Streaming, SaaS

Ralf Reichert is the Co-CEO, Founder, and Chairman at ESL FACEIT Group. Ralf Reichert attended the University of Duisburg-Essen.

## Carsten Maschmeyer
- Type: Angel
- Location: Hanover, Niedersachsen, Germany
- Relevant deals: 5
- Stages: Seed, Angel, Series A
- Focus: Software, Information Technology, Artificial Intelligence

Carsten Maschmeyer is a successful entrepreneur, consultant and financial investor. He was born on May 8, 1959 in Bremen and grew up in Hildesheim. After his graduation in 1978 Maschmeyer completed military service before he began to study medicine in Hannover. To finance his studies, he worked part-time in sales of investment advice to it in 1982completely dedicated financial advice. More about Carsten Masch Meyers consultant. In 1988 Carsten Maschmeyer to AWD financial group, which was successfully launched on the stock market in 2000 and rise to the MDAX and expanded in 11 countries. Was sold in 2007 Carsten Maschmeyer all his shares in the company at the insurance group Swiss Life, who renamed the AWD in AWD Holding. Maschmeyer has today different occupational focuses, inter alia, as entrepreneur, investor and consultant. His experience Carsten Maschmeyer a sought-after speaker on the subject of success. Motivated by the desire expressed by many listeners to learn more about his secret of success, Carsten Maschmeyer published in the spring of 2012 his book "Self Made - performance live richly". In it he describes the basis of his own exciting path and the celebrities strategies for professional, financial and personal success.

## Robin Haak
- Type: Angel
- Location: Berlin, Berlin, Germany
- Relevant deals: 4
- Stages: Seed, Pre-Seed, Series C
- Focus: Software, SaaS, Artificial Intelligence

Robin E. Haak is a German political scientist, tech entrepreneur, operator, and investor with a track record of founding, scaling, and exiting companies—as well as building and managing high-impact funds.He co-founded the AI/ML job matching platform Jobspotting, which later merged with SmartRecruiters. Through the merger, Haak became ashareholder, as well as Global COO and Managing Director of SmartRecruiters, where he built international go-to-market and fundraising operations. Under his leadership the company scaled strongly, surpassing $100M ARR, achieving unicorn status, and was acquired by SAP; SmartRecruiters is now fully integrated into SAP.Beyond that exit, Haak has invested in nearly 100 companies globally, spanning early-stage angel through growth equity. Notable investments include N26 (as the first check investor), Algolia, Aircall, Frontify, Coralogix, Epsor, Planity, Platform.sh, Wo\men Inc., Arx Robotics, and many others.He co-founded Wo\men Inc., a platform advocating for gender equality and diversity in technology, where he contributed as Founder and Chief Marketing Officer.Haak also co-created Revaia, a Paris–Berlin growth equity fund with an ESG and crossover strategy. He was central to raising its first €250 million fund, which has since grown to approximately €600 million assets under management.Today, Haak leads Robin Capital, a Solo GP venture capital firm that has now entered its second fund generation. Starting with €15 million in committed capital in Fund I, Robin Capital has expanded its focus beyond enterprise and B2B SaaS into deeptech, robotics, AI, and highly defensible products. The firm continues to back exceptional founders across Europe, with particular strength in the DACH region.In addition to founding and investing, Haak serves on several boards and advisory roles — including as Advisory Board Member of Slush and Stepstone — leveraging his experience to support founders, guide strategy, and scale businesses.Haak studied Political Science (with emphasis on History, Law, and Theology) at the University of Salzburg, and holds an MBA in Media Management from the Hamburg Media School / University of Hamburg.Outside his professional work, he has a deep interest in viticulture and spends part of each year harvesting grapes at Domaine de la Romanée-Conti in Burgundy, which he sees as a grounding counterpoint to the fast pace of venture capital. He also used to fight Muay Thai in Thailand, still trains regularly, and enjoys traveling, cooking, and reading.

## Sinan Güler
- Type: Angel
- Location: Istanbul, Istanbul, Turkey
- Relevant deals: 4
- Stages: Seed, Pre-Seed, Series A
- Focus: Apps, Fitness, Wellness

Sinan Güler is a Co-Founder at Guler Legacy. He attended Carroll College.

## Verena Pausder
- Type: Angel
- Location: Berlin, Berlin, Germany
- Relevant deals: 4
- Stages: Seed, Pre-Seed, Series A
- Focus: Food and Beverage, E-Learning, EdTech

Verena Pausder

## Dr. Cornelius Boersch
- Type: Angel
- Location: Zürich, Zurich, Switzerland
- Relevant deals: 4
- Stages: Seed, Series A
- Focus: E-Commerce, Software, FinTech

Dr. Cornelius (“Conny”) Boersch is an entrepreneur, business angel and founder of numerous technology companies. Conny is considered one of the bestconnected networkers in the tech and start-up scene. He is the founder of the global company builder Mountain Partners as well as the global co-investment company Conny & Co. Conny initiated theEntrepreneurs Day at the Tegernsee, one of the most exclusive conferences in Europe and regularly holds speeches at universities or tech events all over the world. As a business angel, he has invested in more than 300 companies since 1995 and was voted “European Business Angel of the Year” in 2009. He is a European Investment Fund (EIF) - certified super angel, which means that, subject to certain restrictions, the EIF matches all of his startup investments 1 to 1.As an entrepreneur, Conny previously founded the stock-listed RFID-based companies ACG, Smartrac and Identiv as well as the cashless payment systems provider Sandpiper. For his activities he was named “Entrepreneur of the Year” in 2000. Politically, Conny acted as advisor to Dr. Guido Westerwelle, former president of the German Liberal Party, FDP, Vice-Chancellor and Foreign Minister of Germany from 2009 to 2012.He studied at the European Business School in Oestrich-Winkel and earned his Ph.D. from the University of Essen with a thesis on venture capital and investing. He later also acted as honorary professor and held lectures at the University of Essen.

## Christophe Maire
- Type: Angel
- Location: Berlin, Berlin, Germany
- Relevant deals: 4
- Stages: Seed, Pre-Seed, Angel
- Focus: Software, E-Commerce, Financial Services

Christophe F. Maire is the Founding Partner and CEO of Atlantic Labs, a Berlin-based seed investor dedicated to identifying and investing in innovative digital startup companies. In the last 20+ years, Christophe has built an international track record both as a founder; including gate5 (sold first to Nokia and later developed into HERE and sold tothe German automotive industry) and Plazes.com (also sold to Nokia); and as a farsighted investor named best “European Seed Investor” by Techcrunch two years running. Exited investments include Brands4Friends (eBay), Readmill (Dropbox); StudiVZ, Fyber and Plista. Recent investments led by Atlantic Labs include Medigo, Clue, Jodel, and Campanda, amongst others. Christophe remains actively involved in all his investments, including as a board member of Soundcloud, EyeEm, and Monoqi, and an active promoter of the Berlin startup ecosystem.

## Florian Leibert
- Type: Angel
- Location: San Francisco, California, United States
- Relevant deals: 4
- Stages: Seed, Series A, Pre-Seed
- Focus: Software, Information Technology, Artificial Intelligence

Florian Leibert is the General Partner at 468 Capital. Since 2013, he has served as CEO of Mesosphere, Inc., an Internet start-up based on the open-source software Apache Mesos, which his best friend from high school wrote. His daily responsibilities include creating high-level software structures and managing the firm's finances, recruiting,business operations, and product support. Among his other achievements at Mesosphere, he created Marathon, a scheduler that operates on top of the Mesos software. Florian Leibert also acquired nearly $50 million in funding for the firm from prominent investors like venture capitalist firm Andreessen Horowitz. Concurrent with his role at Mesosphere, Flo Leibert serves as an investor with Taptalk and Driftt.Prior to founding Mesosphere, Flo Leibert held software engineering positions at prominent internet sites, including Airbnb, Twitter, Ning, and Adknowledge. At age 16, he co-founded online marketplace Knaup Multimedia in Germany.

## Roman Kirsch
- Type: Angel
- Location: Berlin, Berlin, Germany
- Relevant deals: 3
- Stages: Seed, Pre-Seed
- Focus: E-Commerce, Software, Mobile

Roman Kirsch is the Entrepreneur and Investor of Rapid Pioneers Group.

## Mustafa Vardalı
- Type: Angel
- Location: Istanbul, Istanbul, Turkey
- Relevant deals: 3
- Stages: Seed, Angel, Series A
- Focus: Apps, Fitness, Software

Mustafa Vardalı is the CMO & Founder at Teknasyon.

## Martin Sinner
- Type: Angel
- Location: Berlin, Berlin, Germany
- Relevant deals: 3
- Stages: Seed, Pre-Seed
- Focus: Software, Internet, SaaS

Martin Sinner is the COO at 360dialog.

## Alper Akcan
- Type: Angel
- Relevant deals: 3
- Stages: Seed, Angel
- Focus: Apps, Fitness, mHealth

Alper Akcan

## Kai Hansen
- Type: Angel
- Location: Berlin, Berlin, Germany
- Relevant deals: 3
- Stages: Seed, Series A, Pre-Seed
- Focus: Software, E-Commerce, FinTech

business angel // entrepreneur // founder lieferando.de // boardmember booksy.com

## Nils Wilde
- Type: Angel
- Relevant deals: 3
- Stages: Pre-Seed, Seed, Angel
- Focus: Information Technology, Apps, Music

Nils Wilde

## Chris Hitchen
- Type: Angel
- Location: Munich, Bayern, Germany
- Relevant deals: 3
- Stages: Seed, Pre-Seed, Series A
- Focus: Software, SaaS, Internet

Chris is an Australian entrepreneur and investor based in Munich, Germany. He co-founded Australia's largest comparison shopping site Getprice.com.au in 2005 and sold it to News Corp in 2010. He became News Corp's Executive Director of Commerce before leading a management buyout of Getprice in 2012, then repositioned the business asNext Commerce, including acquiring south east Asian price comparison Pricepanda and securing investment from Rocket Internet, Tengelmann Ventures, PLDT and Kinnevik, before selling the group to UK-listed Future plc in 2016.Chris also co-founded programmatic video business Audience TV, native ecommerce advertising company Hynt.com and the autonomous vehicle software company Unleash Aerial.Chris is also the founding investor and chairman of Munich-based vacation rentals business Holidu and an industrial advisor to Swedish private equity group EQT.

## Ulf Stahrenberg
- Type: Angel
- Location: Berlin, Berlin, Germany
- Relevant deals: 3
- Stages: Seed, Series A, Series B
- Focus: Education, Mobile Apps, Reading Apps

Ulf Stahrenberg is a product director at Oply GmbH. Prior to this, Ulf served as chief product officer at MONOQI. He held positions at Zalando, txtr, and Strategies4Change.

## Patric Fassbender
- Type: Angel
- Location: Cologne, Nordrhein-Westfalen, Germany
- Relevant deals: 2
- Stages: Seed, Pre-Seed, Angel
- Focus: Education, EdTech, Mobile

Patric Fassbender is the Co-Founder and Managing Partner at Boxine.

## ISB Investitions- und Strukturbank Rheinland-Pfalz
- Type: Angel
- Relevant deals: 2
- Stages: Seed, Series A
- Focus: Software, Apps, Battery

ISB Investitions- und Strukturbank Rheinland-Pfalz

## Frederick Roehder
- Type: Angel
- Relevant deals: 2
- Stages: Angel, Pre-Seed
- Focus: Mobile, Soccer, Natural Language Processing

Frederick Roehder

## Christian Greb
- Type: Angel
- Relevant deals: 2
- Stages: Seed, Angel, Pre-Seed
- Focus: Mobile, Soccer, Natural Language Processing

Christian Greb

## Rouven Dresselhaus
- Type: Angel
- Location: Berlin, Berlin, Germany
- Relevant deals: 2
- Stages: Series A, Seed, Series B
- Focus: Software, E-Commerce, Internet

Rouven Dresselhaus is Co-Founder and Managing Partner at Cavalry Ventures. His most notable investments at Cavalry include McMakler, Forto and Planetly (acq. by OneTrust). He also serves on numerous boards, e.g. at BRYTER and Sofía.Rouven started his career at Morten Sondergaard and then moved to Capnamic Ventures. In parallel, as a member of theadvisory board, he spearheaded the digitization initiative of his family business Joseph Dresselhaus GmbH & Co. KG (acq. by Nimbus) comprising core processes such as finance, HR, logistics and procurement.Rouven has invested in more than five dozen startups and participated in over two hundred funding rounds. He is a member of YPO, a global community of chief executives, and has been mentoring young entrepreneurs in formats such as Techstars, Techstars SAP.io, next logistics accelerator and the Axel Springer Plug and Play Accelerator. In addition, Rouven is a supporter of the entrepreneurial charity Founders Pledge.

## Klaas Kersting
- Type: Angel
- Location: Karlsruhe, Baden-Wurttemberg, Germany
- Relevant deals: 2
- Stages: Seed, Pre-Seed
- Focus: Gaming, Mobile, E-Commerce

Klaas Kersting is a serial entrepreneur (Gameforge / flaregames / Phoenix Games) and Seed-/Early-stage investor in startups in games and e-commerce. He served and serves as board member and advisor to several of his investments.Most recently, in 2019, Klaas founded Phoenix Games, a company aiming to help game founders to achievemore - both financially as well as commercially. In 2008 Klaas Kersting was named 'Entrepreneur of the Year'. Gameforge was awarded 'Red Herring 100 Europe', and 'Technology Fast 50 Rising Stars'. Furthermore, he was selected 'Technology Pioneer 2009' by the World Economic Forum.

## Peter Read
- Type: Angel
- Location: London, England, United Kingdom
- Relevant deals: 2
- Stages: Seed, Series E, Series F
- Focus: Software, Apps, Mobile

Peter is a partner at Vitruvian; a venture partner at BlueYard and LocalGlobe; an advisor to Entrepreneur First, Future Positive Capital, and StrongMinds; and a Trustee of Frazzled Cafe, Doteveryone, and the Oxford Mindfulness Centre. He is an angel investor/advisor in over 100 tech startups

## Robert Ermich
- Type: Angel
- Relevant deals: 2
- Stages: Pre-Seed, Seed, Angel
- Focus: Mobile, Soccer, Internet

Robert Ermich

## Yigit Ihlamur
- Type: Angel
- Location: San Francisco, California, United States
- Relevant deals: 2
- Stages: Seed, Series A
- Focus: Apps, Fitness, mHealth

Yigit Ihlamur - Co-founder, General Partner @ Vela Partners

## Rolf Schromgens
- Type: Angel
- Location: Düsseldorf, Nordrhein-Westfalen, Germany
- Relevant deals: 2
- Stages: Seed, Pre-Seed, Series A
- Focus: Internet, Software, Information Technology

Rolf Schromgens - Co-Founder @ leadership.sprouts

## Martin Ostermayer
- Type: Angel
- Relevant deals: 2
- Stages: Seed, Pre-Seed, Series A
- Focus: Education, Apps, Software

CEO of Shortcut Ventures GmbH in Hamburg, Germany.Martin Ostermayer is one of the CEOs of the venture capital firm, Shortcut Ventures, located in Hamburg, Germany. After graduating in Business Administration from the University of Hamburg, Ostermayer received his MBA from the University of San Francisco in 1998, majoring in telecommunicationsand business strategy.In 1999, he set up handy.de, which became Europe’s largest provider of mobile entertainment services with business partners Thorsten Rehling and Dirk Freise. They also created blau.de, the first independent wireless service discounter in Germany, in 2005. They led the company until 2011.

## Joanne Wilson
- Type: Angel
- Location: New York, New York, United States
- Relevant deals: 2
- Stages: Seed, Series A, Angel
- Focus: E-Commerce, Mobile, Retail

Joanne Wilson is based out of New York, New York and is the Founder and Chief Executive Officer of Gotham. Joanne Wilson attended Simmons College.

## Lawrence Leuschner
- Type: Angel
- Location: Berlin, Berlin, Germany
- Relevant deals: 2
- Stages: Seed, Series A
- Focus: Software, Analytics, CleanTech

Lawrence Leuschner is the CEO & Co-Founder at TIER Mobility.

## Tobias Tschoetsch
- Type: Angel
- Relevant deals: 2
- Stages: Angel, Pre-Seed
- Focus: SaaS, Mobile, Soccer

Tobias Tschoetsch is the founder and managing director of Tschoetsch holds a bachelor’s degree in business administration and master’s degree in management from Berlin, Germany.

## Felix Haas
- Type: Angel
- Location: Munich, Bayern, Germany
- Relevant deals: 2
- Stages: Seed, Pre-Seed, Series A
- Focus: Local, Mobile, Sports

Felix Haas is the Executive Chairman and Founder of IDnow. He previously worked at amiando GmbH as a CEO and Co-Founder. Felix Haas attended Stanford University.

## Oliver Roskopf
- Type: Angel
- Location: Berlin, Berlin, Germany
- Relevant deals: 2
- Stages: Seed, Angel, Pre-Seed
- Focus: Banking, FinTech, Insurance

Oliver Roskopf began his digital career at Rocket Internet in 2008. Following this, he became one of the founding team members who created online matchmaking site, eDarling, where he worked until 2010. In 2010 he took up a position as Managing Director of Citydeal, who were later acquired by Groupon. During his time with Groupon Germany herelocated to Sao Paulo in Brazil, returning to Berlin in 2011 to head up marketing for online retail giant, Zalando. He is currently working on a new venture.

## Murat Balcı
- Type: Angel
- Relevant deals: 2
- Stages: Seed
- Focus: Apps, Fitness, mHealth

Murat Balci is an angel investor.

## Yat Siu
- Type: Angel
- Location: Hong Kong, Hong Kong Island, Hong Kong
- Relevant deals: 2
- Stages: Seed, Series A
- Focus: Blockchain, Gaming, Software

Yat Siu is the Strategic Direction of Daydaycook. and also Strategic Advisor of DigitalX. 
Yat Siu is Founder and Chief Executive Officer of Outblaze a messaging communications company that services over 40 million users today based out of Hong Kong.Yat has previously worked for Atari Germany, served as Director and Head of East Coast Operationsfor Lexicor, established Hong Kong Cybercity (the first free web page and e-mail provider in Asia, later renamed Freenation), as well as AT&T Solutions System Integration practice.He has been named a Global Leader of Tomorrow and a Young Global Leader by the World Economic Forum.It has been reported that Yat Siu sold Outblaze messaging to IBM to become Lotus iNotes.Yat is also responsible FON's operations in China.

## Dirk Freise
- Type: Angel
- Location: Hamburg, Hamburg, Germany
- Relevant deals: 2
- Stages: Seed, Pre-Seed, Series A
- Focus: Education, Software, TV

Dirk Freise - Managing Director @ non olet

## Elio Leoni Sceti
- Type: Angel
- Location: London, England, United Kingdom
- Relevant deals: 2
- Stages: Series B, Seed, Series A
- Focus: Software, Lifestyle, Artificial Intelligence

Elio Leoni Sceti is the Co-founder & Chief Crafter of The Craftory. He previously worked at Beamly as a Chairman & Seed Capital. Elio Leoni Sceti attended LUISS Guido Carli University.

## Jochen Engert
- Type: Angel
- Location: Munich, Bayern, Germany
- Relevant deals: 2
- Stages: Seed, Pre-Seed, Series A
- Focus: Software, Rental, Travel

Jochen Engert - Founder & CEO @ FlixBus

## Ebru Dorman
- Type: Angel
- Location: Istanbul, Istanbul, Turkey
- Relevant deals: 2
- Stages: Seed, Pre-Seed, Equity Crowdfunding
- Focus: Health Care, Apps, Fitness

Ebru Dorman

## Philip Magoulas
- Type: Angel
- Location: Munich, Bayern, Germany
- Relevant deals: 2
- Stages: Pre-Seed, Seed, Angel
- Focus: Software, iOS, Apps

Philip Magoulas is the CFO & Co-Founder at Bestsmile. Additionally, Philip Magoulas has had 1 past job as the Co-Founder & Managing Director at Shore.

## Philipp Herkelmann
- Type: Angel
- Location: Berlin, Berlin, Germany
- Relevant deals: 2
- Stages: Pre-Seed, Seed, Angel
- Focus: Software, Information Technology, Artificial Intelligence

Philipp Herkelmann is Partner at Entrepreneur First. Previous at X-The Moonshot factory in Palo Alto (US) , Google in Berlin (DE) & Dublin (IR)  founder at GiftMe Ltd. and Product Manager at an Ecommerce Venture (DE). He attended Zeppelin University, Friedrichshafen and has a major in Public Management & Governance.

## Daniel Krauss
- Type: Angel
- Location: Berlin, Berlin, Germany
- Relevant deals: 2
- Stages: Seed, Series A, Pre-Seed
- Focus: Software, Rental, Information Technology

Daniel Krauss was born in 1983 in Neheim-Hüsten.He studied Economic Sciences at the FernUniversität Hagen. Daniel has generally worked in the IT area for Marquardt GmbH, IFS AB and Siemens AG. Before co-founding Flixbus in 2011, he was a Technical Account Manager at Microsoft for three years. Now Daniel is CIO of Flixbus, which was able toestablish Europe’s largest intercity bus network.

## Julius Göllner
- Type: Angel
- Location: Berlin, Berlin, Germany
- Relevant deals: 2
- Stages: Seed, Pre-Seed, Angel
- Focus: Software, SaaS, E-Commerce

Julius Göllner - Co-Founder @ ARRtist Summit

## Alex Luik
- Type: Angel
- Relevant deals: 2
- Stages: Angel, Pre-Seed
- Focus: Mobile, Soccer, Natural Language Processing

Alex Luik

## Marcus Stahl
- Type: Angel
- Location: Cologne, Nordrhein-Westfalen, Germany
- Relevant deals: 2
- Stages: Seed, Pre-Seed, Angel
- Focus: Education, EdTech, Mobile

Marcus Stahl is the Co-Founder & Managing Director at Boxine.

## Helmut Nanz
- Type: Angel
- Location: Stuttgart, Baden-Wurttemberg, Germany
- Relevant deals: 2
- Stages: Seed, Series A, Series B
- Focus: mHealth, E-Commerce, Health Care

Helmut Nanz

## Marc Griefahn
- Type: Angel
- Location: Hamburg, Hamburg, Germany
- Relevant deals: 2
- Stages: Seed, Pre-Seed
- Focus: Mobile, mHealth, Internet

Marc Griefahn is Chairman of Weinmann Emergency, the leading respiratory resuscitation company, with headquarters in Hamburg, Germany. Marc is also a venture Investor in Germany and Great Britain.
Marc has a Masters in Economics from Hamburg University. He is married with three kids.

## Mustafa Sevinç
- Type: Angel
- Relevant deals: 2
- Stages: Seed, Angel
- Focus: Apps, Fitness, Health Care

Mustafa Sevinç is the CFO and Founder at Teknasyon.

## Bradley Horowitz
- Type: Angel
- Location: Palo Alto, California, United States
- Relevant deals: 2
- Stages: Seed, Series A, Series B
- Focus: Software, Information Technology, Artificial Intelligence

Bradley Horowitz is an Advisor and Vice President of Product Management at Google. Most recently he helped create Area 120, Google's incubator for internally-sourced innovation.  He's led a large number of products, programs and initiatives at Google - including Google for Startups, Google Photos, Gmail, Google Voice, blogger, and GoogleNews.Before joining Google in February 2008, Horowitz was Yahoo's vice president of Advanced Development where he drove the acquisitions of Flickr and MyBlogLog, launched the Brickhouse incubator and developed new products like Yahoo! Pipes. Additionally, he was responsible for the company's initiative to open up its platform which included overseeing the Yahoo Developer Network (YDN).Previously, he was co-founder and CTO of Virage, where he oversaw the technical direction of the company from its founding through its IPO and eventual acquisition by Autonomy.Horowitz was a PhD candidate at the MIT Media Lab. While at the Media Lab, he worked on a number of topics related to computer vision, graphics and image processing, which resulted in a patented new technique for the recovery of structure, motion and camera parameters from video sequences.Horowitz holds an MS in Media Science from MIT and a BS in Computer Science from the University of Michigan.

## Nikolaus Glasmacher
- Type: Angel
- Relevant deals: 2
- Stages: Angel, Pre-Seed
- Focus: Mobile, Soccer, Natural Language Processing

Nikolaus Glasmacher