The Klein Tools Lineman's Insulating 4-in-1 Box Wrench (KT223X4-INS) is the only double ended 4-in-1 wrench on the market to meet the ASTM standard 1000V rating. It features a transparent handle that shows the metal ends of the wrench are not touching. The solid, durable wrench features four 12 point socket sizes: 1/2", 9/16", 5/8", and 3/4".