Description: 【Material and Comfort】: This running vest is made from polyester and , featuring a lightweight breathable mesh panel. It is highly flexible, comfortable, making it great for trail running training and , road running, and marathons. 【Hydration Capacity】: The vest comes with 2 hydration bladders made from safe materials. This ample water storage capacity meets the hydration needs of outdoor activities. 【Adjustable Fit & Features】: The lightweight backpack vest has adjustable straps to fit your size perfectly. It also features reflective stripes that glow at night ensuring safe running or cycling after dark. 【Storage Space】: The running vest offers enough pockets to store your essentials like mobile phones, keys, rain jackets, water bottles, hydration flasks, bladders, etc., during outdoor activities. 【Versatile Use & Compact Design】: Designed for road biking, running hiking with a compact structure that keeps your back stable without creating much wind resistance. Specification: Material: Polyester and Size Chart: M: 40cmx40cm/15.75inchx15.75inch, subrib circumference 80cm-105cm/31.5inch-41.34inch L: 45cmx42cm/17.72inchx16.54inch, subrib circumference 90cm-110cm/35.43inch-43.31inch Water bottle: 450ml Package Includes: 1 hydration vest 2 bladders Note: Please allow slightly errors 1-2cm differences due to manual measurement.