I got a small one on E-bay for a lawn mower, it is also a hour meter, I used a strip of double back tape. Get the tape made by 3M, I put it on top of the speed meter, It is small 11/2X 1. Only needs to wrap one wire from unit around spark plug wire. When I go 50 MPH It showes that 5500 RPM. At 64. MPH 7700 , I only cost $10 with shipping!