Amprobe VP-1000SB Non-Contact Voltage Probe with Shaker, CAT IV 1000 V 100% safety guaranteed: dual insulated, CAT IV 1000V safety rating, no exposed metal or conductive parts An essential tool when checking for voltage in your home: simply hold the VP-1000SB next to the system to test, including extension cords, light sockets/outlets, GFCI protected outlets, and light fixtures Alerts you with a bright LED light, loud clear tone and vibration when when voltage from 90 - 1000V ac is detected. (Compare to our VP-1000 model, with only a light alert.) Easy to use: always on, no buttons - simply touch and test!