Steelman Pro 78922 Bluetooth Trailer Tester PERFORM SOLO CHECKS - Handy tool allows users to quickly and efficiently test trailer signal lights by themselves 7-PIN FLAT CONNECTOR - Connects easily to 7-pin flat receptacles used on vehicles for trailer connectors FREE APP - Free downloadable app connects to device via Bluetooth to display malfunctioning signals TEST MULTIPLE LIGHTS - Test brake, reverse, and running lights as well as turn signals, 12V charge lines, and even electric trailer brakes EASE REPAIRS - Tool helps to quickly diagnose and fix the exact malfunction for safer driving