Fits M4, M16 firearms. Fast loading, lockable metal cross bar. Hi-density foam tray option for 10 firearms with scopes. Rigid polyethylene tray option for 12 firearms. Detachable halves serve as mobile firearm racks. Humidity gauge changes color above 40%. 4 heavy duty wheels for one-man mobility. Manual Pressure Equalization Valve. Watertight, crushproof, and dust proof. Open cell core with solid wall design - strong, light weight. Easy open Double Throw latches. O-ring seal.