Hydrapak’s soft-sided Flux hydration bottle eliminates the bulk of an empty water bottle while being 60% lighter than a hard-sided bottle. Made of durable dual-layer TPU w/RF welded seams, it is spillproof, packable, & screw-filter compatible. Ideal for hike, bike, & travel, weighing just 2.7 ounces. 100% BPA & PVC free.