Lightweight and compact, the Hydrapak's UltraFlasks™ collapse as you drink. This eliminates sloshing and allows you to pack the empty flask tightly to stow on the go. Perfect for integrating into hydration vests, belts, or handheld systems. Suited for a full range of year round activities, and backed by Hydrapak's leakproof warranty. 500ml/17oz

Features:

• 500ml
• 28mm wide opening
• High-glow bite valve auto-seals after each sip and includes a twish locking cap for added security
• Made of ultra durable, abraision resistant TPU and RF welded seams for superior durabilitiy and elasticity
• Wide working temperature range (can be frozen)
• Safe and reliable 100% BPA and PVC free