Hopkins Tow Doctor (TM) 4 Wire Flat/6 Pole Round/7 RV Blade Trailer Wiring Circuit Tester 50928 02-0230

Trailer side circuit tester adapts to 4 wire flat, 6 pole round, 7 RV blade. Includes a 20 foot extension cord. Tow Doctor is designed so one person can make sure a trailer has been wired properly and all functions are working. Includes battery terminal clips and can be used with any 12 Volt battery.