Flexible bottles get an upgrade. The HydraPak Flux 1L Water Bottle - Mammoth Grey is shaped like a hard bottle, compresses like a soft flask, and cuts weight by 60 percent. Topped with a spill-proof twist cap for grab-and-go hydration, plus a bail handle to keep hydration secure in your hand or on your pack. Finish your drink, and this bottle packs down to earn its space in your pack. With the Flux, innovation fuels performance.