The 12V Relay Tester is a professional auto automotive tool designed for testing electric relays and components in heavy-duty and commercial vehicles. This electric relay tester includes 4 & 5 pin options for connecting to the vehicle's relay, as well as battery clips for convenient power source access. Made of durable plastic, this tester comes with a user guide and clamps for ease of use. Ideal for diagnosing automotive electrical systems, this product is a must-have for car enthusiasts and professionals looking to ensure smooth and reliable performance on the road.