Method of Measurement: The energy meter is equipped with photoelectric coupling power pulse test output port, is located in a wiring terminal box. Connect the test equipment +5VDC to the terminal of 17 (positive terminal), and the signal line connect to the terminal of 18 (negative terminal). Size: Approx. 12 x 10 x 6.5cm/4.72 x 3.93 x 2.55inchWeight: 519gPackage Included: 1 x Energy MeterNote: Please note that the new type and old type of this product will be sent randomly, and make sure you will not mind before ordering Specifications: Standard: IEC62053-21 Display: 6-digit Operating Temperature:-25 ~ + 55 Voltage: 3 x 220/380V Current: 3 x 20(80A) Frequency: 50Hz Impulse constant: 400imp/kWh Operating Humidity: 95% Installation and Use: 1.