Description:High Capacity and Comfort: This Hydration Pack is a lightweight, breathable backpack with a capacity of approximately 12L. It features a double stability system for comfortable wear during outdoor activities like cycling, running, or hiking. The material used is water resistant polyester that is light, thin, comfortable, quick drying and resistant to wear and tear.Reflective Design: The hydration backpack has a reflective design that enhances visibility in low light conditions making it for night time activities. Size19cmx9cmx40cm/7.48inchx3.54inchx15.75inch.Breathable and Durable: This 12L cycling bag is made of polyester, known for its breathability and durability, making it ideal for outdoor activities like running, cycling, or hiking.Ample Storage Space: With 10 storage compartments thoughtfully laid out for easy access, this bag can accommodate all your essentials efficiently. It even includes a shoulder strap zippered compartment that can fit a phone.Adjustable and Versatile: It features an adjustable chest system that can be quickly disassembled and adjusted for tightness making it easy to use. Additionally, there are external hanging devices with reflective strips 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: PolyesterSize Chart:19cmx9cmx40cm/7.48inchx3.54inchx15.75inchSubcostal Circumference: 70cm-130cm/27.56inch-51.18inchPackage Includes:1Hydration PackNote:Please allow slightly errors due to manual measurement and different monitors.