1. with built-in converter 2. for 1 phases, 3P, 3W, 3P4W 3.Voltage: 50V 100V 220V ... meter(watt meter)Power MeterWattmeters or Varmeters with built-in converter for 1 phases, 3P, 3W, 3P4W.Models:HH-96 HH-72Class ... transformer or secondary current 5A CT.wattmeters with buil-in converter for 3P 3W,3P 4W and single phaseModel: HH-96 HH ...