GearWrench 81125 1/4” Drive Locking Extension 4” The GearWrench 1/4” drive locking socket extension features a knurled grip that provides a non-slip surface. The GearWrench 1/4” drive locking socket extension is coated in a professional, full polish finish. The GearWrench 1/4” drive locking socket extension features a locking mechanism that keeps drive tools from disconnecting.