voltage tester Five sensitivity adjustments Press the "S" button to adjust the sensitivity for 5, andstart the default 1st gear: the lowest ensitivity, the5th gear: the highest sensitivity. Sound and light alarms Non-contact voltage tester ensures safety with sound and light alarms,if detects AC signals, activating lights and beeping with varying frequencies. Low Power Consumption The voltage tester has an automatic shutdown function, which will automatically shut down if no operation within 5 mins. Humanized Pen Holder ANENG VD802 Voltage tester pen compact and portable, humanized pen clip design,easy to carry and use.