Features: 1. Compatible with standard 7-way blade trailer sockets. 2. LED indicator for circuit continuity tests. 3. Plug and Play easy installation. 4. Compact and small - easy to put away. Specification: 1. 7 WAY TESTER 2. Material:Plastic 3. Voltage: 12V 4. Pin:7 Instruction: 1. Plug the tester into the mating plug of vehicle. 2. Perform a function test for each circuit.