ITEM NAME:7Pin 12V RV Trailer Boat Socket Circuit Light Plug Tester Socket LED Adapterâ„–[ Feature: Heavy duty nylon housing. Bright LED indicator lights. Easy and quick to test trailer circuits on most trucks. 7-way flat tester can check all your trailer light circuits on your vehicle. Tests 6 separate trailer light functions: Turn, brake, tail, stop, reverse and 12V. Works with both the common 7 way trailer plug used on most SUV's, trucks, boats, trailers and RV's. Confirms you have the 12 volt power supply (often needed to charge batteries or operate interior lights on cargo trailers) which often blow fuses. Specification: Color: Black Voltage: 12V Pin quantity: 7 With LED light: Yes Suitable for: UV's, trucks, boats, trailers and RV's Note: Please allow 1-3mm error due to manual measurement..7-way flat tester can check all your trailer light circuits on your vehicle. Works with both the common 7 way trailer plug used on most SUV's, trucks, boats, trailers and RV's. Tests 6 separate trailer light functions: Turn, brake, tail, stop, reverse and 12V.