Single phase, 3-wire, 4-jaw, 600 V maximum. Jaws fabricated from high conductivity, tin-plated, copper alloy. Insulating jaw support blocks of high impact, non-tracking thermoset polyester. Galvanized steel enclosure. Safety guides reduce chances of accidental contact and aligns meter in sock. Uses RX style hub (not included). Provision for 5th jaw and closure plate included, no bypass. UL listed.