Features:  1: Parameters: ac power meter voltage measuring range is AC 40.0-300.0V/C 250.0-450.0V, current measuring range is 0-100A, active power range is 0-450000W, electric energy range is 0-99999kWh. Frequence: 45.0Hz-65.0Hz, Power Factor :0.00-1.00PF.  2: 178 degree wide viewing angle, high definition color LCD screen, very clear.  3: Two Type Can Choose: Built-in CT or External CT Make wiring easier.  4: Electricity usage monitor: Monitor is the killer of the high-cost energy appliance, helping you lower power consumption and save money.  5: Auto Store & Memory Function: when power off, the electric energy data will be stored and memorized, can be reset.     Specification:  Accuracy: 1%±2 words.  AC voltage Range: AC 40.0-300.0V/C 250.0-450.0V.  AC Current Range: AC 0-100.0A.  Current resolution: 0.01A.  Frequency: 45.0Hz-65.0Hz.  Power Factor: 0.00-1.00PF.  Protruding part size: 54mm x 45mm x 16mm.  Installation width=3P (DZ47/C45 air switch position) Electric Power: 0-450000W, the electric power resolution is 0.1W when measure electric power between 0-9999.9W, otherwise the electric power resolution is 1W.  Electric Energy: 0-99999kwh, the display of electric energy resolution is 0.01kwh when measure electric engery between 0-999.99kwh, the display of electric energy resolution is 0.1kwh when measure electric engery between 1000.0-9999.9kwh and the display of electric energy resolution is 1kwh when measure electric engery larger than 9999.9kwh.  Built-in CT wiring diagram:  When power on, the meter display the measure parameters.  When power on, you can press the button of SAM CK last for 5 seconds,  then the electric energy will to be zero and start to cumulate when release the button.  And when power off, the meter can save the value of electric energy and go on cumulating data when the meter power-on next.     Package included:  1 x Digital Single Phase Energy Meter