Non-Contact Voltage Detector- The insulated housing of the voltage detector ensures safety. Testing can be done without physical contact, and the insulated operation ensures safe testing. Portable Pen-Shaped Design- The voltage detector pen is designed in a pen shape with a pen clip. It can be easily attached to your pocket and many other places, allowing you to keep it handy during repairs, making your work easier. Adjustable Sensitivity- The sensitivity is adjustable for more sensitive and flexible measurements. Press the S button to get 3 levels of sensitivity adjustment. One beep indicates low sensitivity, two beeps indicates medium sensitivity, and three beeps indicates high sensitivity, allowing you to adjust the sensitivity according to your needs. It meets many needs in residential, commercial and industrial environments. Audible Alarm and Safety Light- Distinguish between live and dead voltage by different frequencies of alarm sounds. The higher the voltage, the higher the frequency of the audible alarm and the higher the frequency of the indicator light flashing. The white LED flashlight helps illuminate the work area in the dark. Note- Range: 12-1000V AC 50/60Hz. The Volt Pen requires two AAA batteries to operate, for shipping safety, our pens do not include batteries. AC Voltage Detection The tester probe is inserted into the power outlet or near the live wire. When the tester detects the AC voltage signal, the induction voltage signal indicator flashes. According to the detected signal strength, the tester lights up the corresponding signal strength indicator (high, medium and low). At the same time, the hive emits alarm sounds of different frequencies. When inducing an AC voltage signal, the L (low) signal strength indicator flashes; when inducing a higher AC voltage signal, the M (medium) signal strength indicator is long; when induction to the highest AC voltage signal, the signal strength indicator H (lev) flashes 3 times. AC Voltage Range: 12-1000V Frequency: 50Hz / 60Hz Alarm Mode: Audible and visual alarm Operating Altitude (above sea level):