The 5ive Star Gear Hydration Backpacks are designed with a 2.5 liter reservoir and ideal for long missions or adventures. They feature fully adjustable shoulder straps with quick release sternum strap and easy grab handle on top and front of bag. For close-fitting comfort and all-day hydration, this pack delivers. Item is compatible with the 5ive Star Gear 2.5L Hydration Bladder.