Your Go-to Power Screwdriver. The SKIL rechargeable 4V cordless screwdriver unique circuit sensor technology is a patented feature that detects live wires in outlets switches, cords, and fixtures from up to one inch away. Simply hold the cordless screwdriver near the source of electricity and press the detection button. If the circuit is Live, the red light illuminates and an alert sounds. With this feature, you'll always know where live circuits are located before getting started on your project. More about this product: 230 RPM, easy to use, circuit sensor technology, automatic spindle lock feature, integrated rechargeable Lithium-Ion battery, micro USB charging, LED work light.