Hydrate effortlessly with this 500ml flask, designed for compatibility with vestpacks. A WingStay™ removable stabiliser prevents bounce, while a wide-mouth opening makes it easy to load ice or mix in electrolytes. A high-flow valve, easy-grip twist cap and tapered shape simplify hydration. Crafted with durable TPU and RF-welded seams, and compatible with the UltraFlask Filter Cap (sold separately). Features WingStay removable stabiliser prevents bounce Large 42mm opening for quick ice and drink mix loading Tapered shape for easy pocket loading High-flow, self-sealing bite valve Durable TPU- and RF-welded seams Easy-to-grip twist cap