We've always been Professional.Before Probott ®,hydration bottles were made from either polycarbonate plastic or aluminum.We now know that both those materials are associated with a host of diseases and illnesses,info that wasn't common knowledge in 2011 when we released the first food-grade stainless bottle onto the market. But there were studies,even then, that worried us and caused us to doubt the safety of the existing bottles on the market.