The Kor One water bottle is a reusable water bottle that is not made from polycarbonate (therefore doesn't have any Bisephenol-A hazards). The Kor One is made from Eastman Tritan, a copolyester which is a preferred alternative to polycarbonate. Copolyester's biggest advantage is that it retains its strength and clarity even when exposed to other chemicals, whereas polycarbonates are more sensitive.