NWT BLACK Premium, durable and breathable design with cushioned 3D Air-Mesh™ back panel Comfort & stability-enhancing design includes removable sternum strap 6.5L storage volume with 3 internal separated compartments Rear compartment acommodates 600 mL - 1.5 L reservoir (not included) with integrated reservoir tube pass-through Unique slide-adjust strap system for optimized fit and convertibility