Description: [Hydration Vest Backpack]:This running vest is designed to hold a 2L water bladder (not included),allowing for quick hydration during your run.It's for medium to long distance running. [Material]:Running vest is made of polyester,lightweight,,and comfortable to wear. [Feature]Ergonomic designed vest bag comes with an adjustable chest strap that guarantees the fit,keeping the pack from bouncing while running. [Multiple Pockets]:The backpack has 10 pockets at the front where you can store items like water bottles,keys,mobile phones,,and more.The back can accommodate items like a bladder. [Versatile Use]:This backpack isn't just for running or hiking; it's also suitable for other outdoor activities such as cycling,mountain climbing,and marathons. New and old soft water bags are shipped randomly Specifications: Material:Polyester Size: S:Length 44cm/17.32inch,Bust 78.5cm/30.91inch (chest circumference 78cm-86cm/30.71inch-33.86inch) M:Length 45.5cm/17.91inch,Bust 83.5cm/32.87inch (chest circumference 87cm-92cm/34.25inch-36.22inch) L:Length 47cm/18.50inch,Bust 88.5cm/34.84inch (chest circumference 93cm-99cm/36.61inch-38.98inch) XL:Length 49cm/19.29inch,Bust 93.5cm/36.81inch (chest circumference 100cm-107cm/39.37inch-42.13inch) XXL:Length 51cm/20.08inch,Bust 98.5cm/38.78inch (chest circumference 108cm-120cm/42.52inch-47.24inch) Note: Please allow slightly errors due to manual measurement and different monitors. Package included: 1 Hydration Vest 2 Water Bag