17oz Quick Stow flask is lightweight, collapsible and features our classic one-piece silicone bite valve for rapid hydration 3D Micro Mesh: Multi-directional air flow and cushioning to maximize comfort and breathability Secure Phone Pocket: Conveniently located with a zipper closure for secured quick access Reflectivity: For early morning or late-night runs Trekking Pole Carry: Easily remove or replace poles while running