Alpinestars Sprint Back Pack 81% Polyamide 19% Polyester Imported 8L capacity. Main chassis constructed form durable rip-stop nylon with PU-reinforced textile. Mesh shoulder strap and back reinforcements for improved airflow. Main compartment for hydration pack (sold as accessory upgrade). Conduit for hydration hose. Highly convenient front compartment pocket with waterproof zipper. 8L ; Main compartment for hydration pack (sold as accessory upgrade) Highly convenient front compartment pocket with waterproof zipper Removable waist belt, plus adjustable sternum strap for secure fitment; Sternum strap incudes whistle to attract attention Mesh shoulder strap and back reinforcements for improved airflow