ALPS Mountaineering Caldera 4500 Internal Frame Backpack Shoulder strap padding wraps to back for maximum comfort; Top pocket converts to a fanny pack; Rain cover included Blue polyester rip stop; Dual aluminum frame stays; Top loading, extendable top lid; Spindrift collar with draw cord; "Over the top" compression strap Hydration pocket and port; Front access to main compartment; Front mesh pocket; Multiple side compression straps; Lower side bottle pockets Lower door: #10 zipper; Internal horizontal divider Torso Range: 17" to 23"; Capacity: 4500 in (74 L); Weight: 5 pounds 15 ounces