?DUAL COLOR LIGHT TUNGSTEN BULB?Adding dual color light for circuit's signal, red light indicates positive polarity green light indicates negative polarity. Also built-in tungsten bulb to illuminate the backside in dark work environments, where provides a bright and reliable light indication, guiding you through intricate electrical tasks to the source of the problem with ease. ?PREMIUM SPRING WIRE ERGONOMIC DESIGN?Maximum extended to 96 inch long enough spring wire increases flexibility and a wide measuring area when testing, anti-bending design of the tail wire makes no worry about bad contact of the line. Along with large size crocodile clip for easy one-hand operation, will definitely improve your working efficiency. ?SHARP PROBE ANTI-LOST PROTECTIVE SLEEVE?Long sharp stainless steel probe for piercing insulation with ease, also for hard to reach tight areas. Integrated anti-lost protective sleeve to secure the probe during storage and safeguarding against damage, making sure no stab and wound and won't be lost wherever you go, which is a thoughtful touch for your auto battery tester. ?SAFE DURABLE USE?This electrical tester pen adopts ergonomic handle for comfort and 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. ?WIDE APPLICATION?DIY automotive circuit tester/circuit test light with 6-24V DC voltage testing range. Quickly check various vehicles electrical circuits and diagnoses issues, including alternator tester functionality for car/truck/SUV/boat charging systems. Also ideal for testing other 6-24v DC wirings and circuits. Making it an essential tool in electrical troubleshooting.