Reese Towpower 85350 Adapter with LED Circuit Tester (7-Way Blade to 6-Pin or 4-Way Flat) Easily adapt OEM 7-way blade connector to either 6-pin round or a 4-way flat connector 6-pole round connector is switchable to meet desired wiring requirements Instantly checks basic trailer electrical circuit for connectivity Displays connectivity using high visibility LED's Hinged dust cover protects 6-pin round when not towing