Hydrapak Flux 1.5L Hydration pack

Amazon

Lightweight and compressible, 50% lighter than a hard bottle and compressible, when empty, to pocket size. High flow nozzle: the high flow drinking nozzle is equipped with a dust cover and can be quickly opened and closed with one hand. Filter compatible: compatible with water filters with 42 mm thread for off-road use, including the HydraPak 42 mm filter cap. Fits in backpack bags. Designed to fit into the backpacks in full condition and be rolled up to save space when empty. Ultra durable: made of two-layer film laminate, with abrasion-resistant TPU and RF-welded seams for excellent durability and elasticity

Snowcountry

The Hydrapak Flux 1.5L is an upgrade for the flexible bottles. The Flux is shaped like a hard bottle, compresses like a softflask, and cuts weight by 50%. Topped with a dust cover and twist-drink nozzle for grab-and-go hydration, plus a bail handle to keep hydration secure in your hand or on your pack. The Flux stands upright like a hard bottle but when you finish your drink, this bottle packs down to pocket size.