Yellow coupling head (included in the vehicle outfit) can be screwed on fitting 3 (Fig. B 2033) of the towed vehicle and then connected with the yellow head 6 (Fig. B 1722) on the towing vehicle by means of a hose. This will allow for control of towed vehicle brakes by the towing vehicle driver and, if "A"-type hitch (Fig. A 7704) is used, no driver has to be in the towed vehicle.