Hopkins 50928 Tow Doctor Trailer End Wire Harness Test Unit<div style="text-align: left;"><strong>[Product Information]</strong><br><ul><li>Designed so that one person can make sure a trailer has been wired properly and all functions are working</li><li>Tests all trailer functions - left turn， brake， tail， backup lights， electric brakes， and auxiliary power</li><li>Trailer lights illuminate and LED lights on the tester show function operation</li><li>Adapts to 4 wire flat， 6 pole round， or 7 RV blade</li><li>For electric brakes， magnets are activated to determine correct operation</li></ul></div><img src="http://ecx.images-amazon.com/images/I/4103x62r9mL.jpg" noproxy><img src="http://ecx.images-amazon.com/images/I/51HyIcYuvPL.jpg" noproxy><img src="http://ecx.images-amazon.com/images/I/61qGOwZy%2BJL.jpg" noproxy>