Heavy duty carabiners designed for both indoor and outdoor use Pressure-treated galvanized steel designed for the toughest applications & highest rust resistance Hex bolt screwlock closure with large opening allows for easy locking/unlocking Ideal for rigging, chain repair, connection points and more Measures 3.5" x 1.6" (9.9mm gauge) NOTE: Not for use in climbing, mountaineering, aerial sports or other extreme activities