【Bright & Reliable Indication】A quality bulb is built in this light tester, where provides a bright and reliable light indication, guiding you through intricate electrical tasks to the source of the problem with ease. Highly visible light indicates circuit's signal, the brightness of the light will be vary with the different measured voltages. 【Safe & Durable Use】This electrical tester pen adopts ergonomic handle for comfort and a safe grip. Constructed with high quality ABS body with higher transparency, shatter-proof and durable, can withstand long-term rough use. Premium insulation protective rubber tip protects you against electric shock, heat insulation and oil resistance for safe operation. 【Bidirectional Current Voltage Testing】You can attach the alligator clamp either to negative or positive ground, while use the probe to touch the other side to diagnose short circuit or defective fuse. Its lightweight and easy to carry, will not take up much space in your toolbox or storage area, convenient to take it with you when you drive out. 【Sharp Probe & Large Alligator Clip】Long sharp stainless steel probe for piercing wires, also for hard to reach tight areas. Anti-bending design of the tail wire makes no worry about bad contact of the line. Along with large size alligator clip for easy one-hand operation, will definitely improve your working efficiency. 【Wide Application】DIY automotive circuit tester/circuit test light with 6-24V DC voltage testing range, ideal for checking various vehicles electrical circuits, quickly check automotive headlights, taillights, turn signal circuits, faulty sockets, fuse connections, also for testing other 6-24v DC wirings and circuits. Making it an essential tool in electrical troubleshooting.