The Lightest Hydration Solution for High-Performance Outdoor UseEngineered for runners, trail athletes, and outdoor adventurers, the Ultralight TPU Soft Flask is designed to fit seamlessly into running vests, waist bags, and hydration packs. Available in 250ml, 500ml, and 750ml sizes, this dark blue flask collapses completely when empty and expands to full capacity on demand — no wasted space, no unnecessary weight.The soft bite valve lets you drink without breaking stride, while the wide-mouth opening makes refilling fast and easy. Food-grade TPU construction means it's safe, durable, and built to handle the rigours of trail and endurance sport.Specifications Feature Details Capacity Options 250ml / 500ml / 750ml Material Food-grade TPU (BPA-) Color Dark Blue Closure Soft bite valve + wide-mouth opening Design Collapsible / foldable Compatible With Running vests, waist bags, hydration packs Why Choose This Soft Flask? Three Size Options: 250ml, 500ml, and 750ml to match your activity and duration. Vest & Waist Bag Ready: Slim profile fits front pockets of most running vests and waist bags. Soft Bite Valve: Drink on the move without removing the flask from your vest. Collapses When Empty: No awkward bulk as you drink down — the flask shrinks with the water level. Food-Grade TPU: BPA-, taste-neutral, and safe for all-day use. I For Trail runners and ultramarathon athletes Cyclists and mountain bikers Hikers using running vests or waist packs Any outdoor activity where weight and space matter In the Box1 × TPU Soft Flask (250ml, 500ml, or 750ml)