Universal 12V Electronic Automotive Relay Tester for Car Van Auto Battery Checker Material: Plastic & Metal Voltage: 12V Features: Automotive relays test tool. Through the continuous automobile battery (11V-15V) to the relay coil, the detector can properly check the relay contact function. The tester observes contact data, closure time, relay inertia at each test stage, etc. Test to properly control the opening and closing of the relay. If the relay is abnormal the red LED will light, it's normal the green LED will light. Package included: 1 x Relay Tester Note: 1. Due to the difference between different monitors or color reflecton in the monitor lighting, background etc, the picture may not reflect the actual color of the item. 2. Please allow 1-5mm error due to manual measurement. 3. The car battery must be a 12V battery, 4.The voltage of the battery must be between 11V-15V. 5. The applicable coil resistance must be above 20 ohms.