["★Lightweight For Running: 5.5L race vest only the backpack weight is 8.82oz/250g super light reducing much of the load during the running.When it comes to running the shorter you plan to spend on the trail the lighter pack youll need.Design for middle or long distance running." ★Hydration System:Bladder compartment with hanging systemAonijie running vest compatible with 2L bladder (not included);2 Front flask pockets with secure loopsMake it easy to drink and stays balanced when you run. "★Multiple Storage Compartment:Designed with 6 exterior pockets you can store all tiny items such as vacuum cup keys walletphone and cash etc. Theres ample room upfront for another bottle wallet keys and other small items. The rear storage is big enough for backup bottle headlamp buff and etc." ★Comfortable Fit Vest Pack: Fully adjustable shoulder and chest straps that guarantee the perfect fit keeping the pack from bouncing while running. Designed with a unique padded back section to allow airflow between your back and the pack.Soft mesh on back and shoulder straps maximize breath-ability. ★Fit You Well: Ergonomic designed vest-shaped bag coming with adjustable waist strap and high elastic chest straptwo sizes for your option.This backpack can be used for more than running and hiking.It is suitable for almost all outdoors activities such as running riding camping marathon etc.]