【High Capacity and Comfort】: This Hydration Pack is a lightweight, breathable backpack, features a double stability system for comfortable wear during outdoor activities like cycling, running, or hiking. 【Storage Design】: The shoulder backpack storage can hold soft water bottles energy gels or other supplies. There's also a zippered compartment on the shoulder strap for small items like cards, phone, etc. 【Quality Material】: Cycling bag water bag is made of nylon fabrics, waterproof, lightweight, thin, comfortable, quick drying, and resistant to wear and tear, making it great for long outdoor adventures. 【Adjustable Buckle】: It features an adjustable chest system that can be quickly disassembled and adjusted for tightness making it easy to use, so to help you release your burden or pressure. 【Multifunctional Use】: Additionally, there are external hanging devices where you can hang warning lights; it also has a mountaineering stick mounting device with elastic rope design for stable carrying without shaking. Specification: Material: Nylon Size Chart:Size: 16.5cmx14.5cmx36cm/6.50inchx5.71inchx14.17inch Recommended Bust: 90cm-105cm/35.43inch-41.34inch Package Includes: 1 Hydration Pack Note: Please allow slightly errors due to manual measurement and different monitors.