1) Self testing before use: Close the tester probe to any hot line bestest will light up together with buzzer sound. If the light and sound are weak please replace the batteries inside

2) Test voltage present: Close the test pin to live parts the tester will light up together with sound

3) Replace batteries: Please refer to the following picture to replace batteries

4) Don't place the tester near high voltage warning:

A. Check before use

B. Never test the voltage which than 1000V AC

C. Test voltage range: 90V-1000V AC

D. IP54 IEC 1010

E. AAA 1.5V/2PCS

F. Battery life: 6 hours for continuous using standby for 1.5 years