Detect voltage in cables, circuit breakers, and more without the need for direct contact with this voltage tester. With a bright green LED that functions both to let you know the tester is working as well as a work light, this tester also features a warning tone and a red LED to alert you when voltage is detected.   Id Klein Tools NCVT-1P Non-Contact Voltage Tester Pen, 50 to 1000 V