20 in 1 Kit: Includes 15 pole probes and 5 4mm banana plugs for alligator clip circuit test leads. The back probe test leads are flexible copper wires. The alligator clips are made of copper alloy. Line length: 30cm. Rated current: 5A. Banana plug: 4mm. Back probe needles: The five-color test leads are made of stainless steel, straight, 45-degree and 135-degree probes, with a needle gauge of 0.7mm. Insulator test voltage up to 30V, suitable for wiring harness connectors, fuel injectors, automotive, industrial, HVAC, electrical, marine sensors, etc. Safe and no damage: As circuit testers, they are used to pierce wire insulation to make automotive electrical measurements without damaging the wires. Color coded for easy identification and measurement. It is also soft to the touch. VERSATILE: The electrical test kit with standard 4mm banana plug test lead connector works with most field test lead kits. Not only for automotive diagnostics, testing and repair, but also for physics labs, schools, homes and industries.