Abstract: A cap unit is mounted on the exhaust end of a tail pipe of a motor vehicle and includes two tubular sections connected by a conical transition section. One tubular section is mounted on the tail pipe adjacent to the exhaust end of the tail pipe and a flap is hingedly mounted on an end of the second section. The flap is mounted to hang down when the cap unit is mounted on the tail pipe so that gravity biases the cap into an exhaust end covering position and exhaust gases flowing out of the tail pipe will move the flap out of the covering position against the bias of gravity. The cap unit provide aesthetic appeal to the tail pipe.