With the JQ Werks Madtrace 6061-T billet aluminum MOMO Horn Cap Adapter, you can easily fit any MOMO size horn cap on your racing steering wheel. Just simply open the factory MOMO horn cap, remove the spring and top piece from the plastic housing, and place them into your new JQ Werks Madtrace MOMO Horn Cap Adapter. Ensure the spring connects to both copper rings, then secure the back cover and screw the assembly onto the hub system.