Kyoritsu 5711 Voltage Tester is a non-contact voltage tester that can be used to detect the presence of AC voltage in electrical circuits. It has a wide voltage range of 100V to 1000V and can be used to test both single-phase and three-phase circuits. The 5711 voltage tester also has a built-in LED flashlight, which can be used to illuminate the work area in low-light conditions. The 5711 voltage tester is easy to use. Simply point the tester at the electrical circuit that you want to test and if voltage is present, the tester will emit an audible and visual signal. The tester has a dual sensitivity mode, which allows you to adjust the sensitivity of the tester depending on the application. The 5711 Voltage Tester is a valuable tool for electricians, technicians and DIYers alike. It is a safe and easy-to-use way to detect the presence of AC voltage in electrical circuits.