Utilize the input text as a context reference, choose the right relationship between Stratasys and 3D printing from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

After all, if there's such a large addressable market for 3D printing in manufacturing, why isn't Stratasys selling more 3D printers?

Answer: product_or_material_produced