It's a centre cap for an aftermarket steering wheel that incorporates the horn button and the buttons for "SET/CAN/RES" to control the cruise control. I have taken pictures below with the dimensions and pics of the back to show you the wires it has. I'm pretty sure it came from a steering wheel on a Lude but was a long time ago!
I have never used/tested it as bought it but then decided on buying and using sparco buttons (like NOS buttons) to control the cruise instead! TBH don't really think these things can go wrong as only 3 buttons and some wires attached so nothing to really go wrong I don't think!
£12 delivered!



