Feature: 1. High Accuracy Measurement: With Hall sensor, through hole design, you can measure the forward and reverse current. without damaging the original circuit, and with calibration potentiometer, it can be adjusted by itself. 2. Dual Digital Display: The meter is compact and can display real time voltage and current values on the same screen at the same time. It adopts exquisite SMT technology, dependable to use. 3. Easy Operation: The current can be detected by passing the wire directly through the hole. The current of the positive and negative pole of the power supply, a certain line or equipment in the line can be measured at will. 4. Resistance to Current Shock: The gauge can test the voltage or current of two completely isolated equipment, and the ammeter will not be damaged by the current impact. The withstand voltage between the ammeter and the measured conductor is up to 2KV. 5. Wide Applications: The voltmeter ammeter can be used for cars, motorcycles, electric bikes and more, used to monitor storage battery, voltage and current change status or other equipment. Specification: Item Type: Volt Amp Meter Material: ABS Test Voltage Range: Range: 300V, Test Range (V): 0.0-300V, Resolution (V): 1V, Resistance (Ω)>1M Test Current Range: Range 20A, Test Range (A):+/-0.10-20A, Resolution (A): 0.1A Size: Approx. 70 x 40 x 30mm / 2.76 x 1.57 x 1.18in Installation Hole Diameter: Approx. 68 x 38mm / 2.68 x 1.5in Measurement Accuracy: 1% (± 2 Bits) Measurement Rate: ≥ 500mS/Time Zeroing Calibration: In order to obtain more accurate measurement, it is recommended to power on preheat for more than 5 minutes before zeroing calibration. Working Environment: Please try not to install the meter head and current transformer around high temperature, strong magnetic field and large transformer, otherwise it will affect the accuracy. Working Current:<30mA Power Supply Voltage: DC 4-30V Working Temperature: - 10-+65 ℃ Working Humidity: 10-80% (No Condensation) Working Pressure: 80-106kPa Exposure To The Sun: Direct exposure is not allowed Display Mode: Full three 2 x 0.39in LED, voltage red word, current green word. Package List: 1 x Volt Amp Meter