This compact voltage tester pen lets you quickly diagnose 6–24V DC electrical systems with a long 13.5 ft cable for easier access to hard-to-reach wiring. Key benefits Accurate voltage testing for 6–24V DC systems — useful for most cars, trucks, motorcycles and auxiliary 12V/24V circuits. Long 13.5 ft cable gives you reach and flexibility to test components without straining or disconnecting wiring. Multi-function: checks voltage polarity, inspects lamps, verifies motors, tests conductivity, and helps trace and locate short circuits. Safer testing: built-in short circuit protection helps prevent damage and gives clearer, more dependable results. Simple, tool-free operation: attach the tester pen to the vehicle battery, then shake the power on-off forward or backward to conduct subtractive and straight polarity from the battery to the tip. What it does (function and performance) Measures and indicates polarity and presence of voltage across 6–24V DC circuits for fast, reliable diagnostics. Traces shorts and continuity to pinpoint faults in wiring and components without extensive disassembly. Tests motors and lamps in situ to confirm whether components are receiving power and functioning correctly. Compatibility and size Designed for 6–24V DC electrical systems (typical automotive and light vehicle applications). Compact pen-style tester with a 13.5 ft cable for extended reach and convenience. Typical use scenarios Locate a parasitic short in a car wiring harness to identify where a fuse keeps blowing. Verify headlight or taillight bulb polarity and continuity before replacing a socket or connector. Check whether a window motor or starter circuit is receiving voltage while troubleshooting intermittent operation. How to use (quick steps) 1. Attach the Voltage Tester Pen to the vehicle battery. 2. Move the power on-off forward or backward (shake) to energize the tester. 3. Apply the tip to the circuit/component under test to read polarity, continuity, or identify shorts. No extra tools required — designed to make common 6–24V vehicle electrical diagnostics faster, safer, and easier.