Looking for a different look for your bike? This adapter makes is possible to mount an original Harley-Davidson fishtail end cap to your Dr. Jekill & Mr. Hyde | The Exhaust. Cause with some bikes the fishtail is an essential part of the look, don’t you think. We offer adapters that fit a Dr. Jekill & Mr. Hyde exhaust and a genuine Harley-Davidson fishtail end cap.