GDYZ-302W Metal Oxide Arrester Tester is composed of a host, a detector, and an insulating rod. The host and the detector adopt wireless communication, the communication distance is 30 meters, the host can remotely open or close the clamp head of the detector to complete the test process, and the host can display the current test value and the status of the clamp head in real time. The detector uses a micro motor to drive the opening or closing of the clamp head. The clamp head is made of high-performance permalloy, which has super anti-interference ability and is hardly affected by external magnetic fields. The resolution is as high as 1uA. The detector can be connected to an insulating rod for testing of zinc oxide surge arresters on high-voltage lines. The meter can also be used as an ultra-high-precision clamp-on leakage current meter.