Sports Bottle - 21oz No more water sloshing, crinkling, or annoying noise, thanks to the biodegradable bottle liner which shrinks as the liquid is used, making it feel more like a solid. No more harmful bacteria or annoying aftertaste, no more bottles to clean, thanks to the disposable fully biodegradable liner. Very flexible and squeezable, fitting your hand comfortably enabling you to get your water or favorite mix on the go. Air space between liner and bottle act as an insulator to keep fluids cooler longer. Patented one way jet stream valve, for accurate and precise flow.