Horn Button Adapter Ring Specifications Made by Momo in 0.7 mm thick galvanized steel this ring is intended to fill the gap between certain combinations of hubs steering wheels and horn buttons. It has a male connector to easily ground the horn terminal and is suitable for any 6x70 mm PCD steering wheel. It acts as a centering ring between the steering wheel (external Ø60 mm) and the hub and horn (internal Ø51 mm). Thickness : 0.7 mm PCD : 6x70 mm Material : galvanized steel External centering diameter : 60 mm Internal centering diameter : 51 mm Overall outter diameter : 80 mm Ground male plug