A special kind of customer...
Medical device manufacturers once did all their custom integrated circuit production in-house, essentially operating as proprietary semiconductor manufacturers. This was done to facilitate compliance with very strict US FDA and international regulations for safety, quality and process control. These controls and more are still in place, and still limit the diversification of their custom chip production processes to foundries and job-shops following the business model now utilized by "normal" semiconductor designers.
Wacom Quartz (and its predecessor company) have provided glassware to the in-house I. C. production department of one of the world's largest biomedical design and manufacturing companies (also the inventors of the wearable, battery-operated pacemaker) since the late 1980's. 
This customer, and other medical device sector customers acquired since, were a major reason the management and owners of Wacom Quartz supported an ISO-9001 quality system since day one and continue to do so. Medical device manufacturers were among the first companies in America to require quality system registration of their entire supply chains.
Wacom employees take pride in the idea that our products are part of the process to make life saving devices. Some of us even have family members who's lives depend on the products from these customers! What better motivation could there be to create top quality quartzware?