GB (Gardner Bender) 6-in-1 Circuit Alert Voltage Sensing Screwdriver with Bonus GFI Tester Gardner Bender voltage sensing screwdriver. Produces both a visual and audible warning when the sensor tip of the tool is in proximity to a live circuit. (Note: Tool should be tested on a kown live circuit to familiarize the user with its proper operation). Includes #1 and #2 Phillips bits, 3/16 and 1/4 slotted bits, and 5/16 and 1/4 hex nut driver bits. Bits store in the tool. Limited lifetime warranty by Gardner Bender. Bonus GFI tester is included. Durable high impact construction. This is a professional grade tool.