DUOYI Digital Earth Tester.
This model is also known as the DY4100 Digital Ground Resistance Tester.
It is used to test the earth resistance of various systems, including power systems, electrical equipment, and lightning conductors.
The tester can measure earth ground resistance from 0 to 2000Ω.
It has a resolution of 0.01Ω and can measure earth voltage from 0 to 30V.