Specifications: Material: ABS Color: Black & Red Power Supply: 8 * 1.5V AA Battery (Not included) Measurement Methods: 1. The earth resistance is measured by the constant current conversion method. This method uses the test current with about 800Hz frequency and about 3MA. 2. The measurement of the earth voltage adopts average numerical rectification method. Working Condition: 0℃~40℃, Relative Humidity Below 85% Storage Condition: -10℃~50℃, Relative Humidity Below 85% Item Size: About 19*14*7cm / 7.48*5.51*2.75in Item Weight: About 586g / 20.67oz Package Weight: 2150g / 75.83oz Package Size: 34*27*9.5cm / 13.38*10.62*3.74in This instrument is controlled by an intelligent microcontroller chip, with high reliability and high accuracy. It can be used to test the earth resistance of various power distribution lines, indoor wiring, electrical equipment, telecommunications, etc. There are two measurement methods: two-pole method and three-pole method. It can also measure the earth voltage. It uses a large liquid crystal display with a backlight, which is easy for the user to read. It has data storage function, which can store 100 sets of measurement data; the data will not be lost when power is lost, which can be convenient for users to have historical data inquiry. In addition to measure the maximum value, minimum value and average value, it has relative measurement function and automatic shutdown function.