Feature: 1. The backpack\u0027s reflective design enhances your visibility in low-light conditions. 2. Two water bottle compartments are set on the shoulder strap, which can hold 250ml soft water bottles or energy gels and other supplies. 3. The shoulder strap mobile phone compartment can hold a 6.7-inch mobile phone, with a sticky buckle design to prevent it from slipping out during exercise. 4. The main bag compartment can hold a 1.5L water bladder or carry-on lightweight clothes and other items. 5. There are two chest circumference adjustment systems, which can be quickly disassembled and adjusted for tightness, simple and easy to use. Specification: Designed for outdoor enthusiasts, this hydration backpack features a 1.5-liter water bag compartment and two water bottle bin, making it versatile for a broad spectrum of users. Whether you're a casual visitor at amusement parks or an avid hiker or professional athlete, this pack is tailored to meet your hydration needs. Features: The backpack's reflective design enhances your visibility in low-light conditions. Two water bottle compartments are set on the shoulder strap, which can hold 250ml soft water bottles or energy gels and other supplies. The shoulder strap mobile phone compartment can hold a 6.7-inch mobile phone, with a sticky buckle design to prevent it from slipping out during exercise. The main bag compartment can hold a 1.5L water bladder or carry-on lightweight clothes and other items. There are two chest circumference adjustment systems, which can be quickly disassembled and adjusted for tightness, simple and easy to use. Specifications: Material: Nylon, polyester, spandex Color: Red/ Yellow/ Grey/ Green/ Blue (optional) Capacity: 5L Size: 38*20*3cm/ 15*7.9*1.2in Weight: 170g/ 6oz Package list: 1 * backpack Package List: 1 * backpack