Purist inner surface uses a flexible glass infusion to keep your water pure & your bottle clean. Watergate cap featured only on the Purist bottle. Has very clever valve inside the poppet. Allows water to flow when you need it, but spill proof if the bottle falls over when poppet is open > 26 & 22oz. versions > Purist inner surface uses a flexible glass infusion to keep your water pure & your bottle clean > New Watergate cap featured only on the Purist bottle. Has very clever valve inside the poppet. Allows water to flow when you need it, but spill proof if the bottle falls over when poppet is open > Large screw cap is leak-free & big enough for ice cubes & powder drink mix > made from super squeezable LDPE material > Clear view strip makes it easy to see contents > Uses BPA-free plastic: 100% FDA food-grade materials, printed with non-solvent base (UV cured), CPSC-approved ink