If you need to cap off the speedo sensor hole for whatever reason, you need this plug Some other companies do this with a steel plate and a gasket, just like old 4-speeds. Ever seen a 4-speed with the speedo cable drive hole capped off this way. It probably showed signs of leakage Our plugs are made of 6061-T6 and include an o-ring and a chrome button head screw For a clean look, our plugs have a low-profile top and they don't leak