Flux 1.5 L Size:1.5l/50 Oz and with the TracPak

and with the TracPak

It also holds more than you'd expect considering its slim

A layer of polyester fill material underneath the contact surface increases airflow for a really comfortable nights sleep even in warmer conditions

has a 40-liter capacity

Flux 1.5 L Size:1.5l/50 Oz and with the TracPakFlexible bottles get an upgrade. The Flux 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.