EKM Metering 120 Volt Pass-Through kWh Meter, 2-Wire (1 hot, 1 neutral), 50A, 60Hz, EKM-15IDS RELIABLE - Accurate to within 1%, LCD readout in hundredths of a kWh, to 99999.99 kWh. EASY TO INSTALL - Simple DIN-rail mounts used for installation. DURABLE - Usage data is stored even if the meter loses power for 10 years. Tamper-proof and meter sealable. REVENUE GRADE - Meter readings can be used for billing purposes. COMPACT - Professional design fits in any room.