This wireless LED tow bar system is ideal for towing larger vehicles like buses, box trucks or tractor trailers. Simply plug the 7-pin transmitter into your truck's connector. The transmitter then "tells" the bar to follow the tow truck's signals for better visibility on the road. The bright LED taillights only come on when the towing vehicle's taillights are on to save on battery power. System includes 36"L lightbar, 7-way transmitter and charge cord. Mounts with rubber cords (included). 20-hr. run time per charge.