Outdoor Military Tactical Backpack Sling Bag Chest Pack Bag Shoulder Backpack with Bottle Holder Tactical Military Sling Chest Pack Bag Chest sliding adjustment system can quickly adjust to their comfortable state,so that more comfortable Backpack. The bag works well with a variety of different outfits and casual styles. MOLLE external expansion system designed to be used in combination with other equipment,you can load pockets,water bottle bag,accessory kits and other. Outer Material: High strength abrasion nylon; Inner Material: Waterproof Silky Cotton