This is a recoil pull start starter designed for small 2-stroke engines.It is specifically compatible with 49cc, 50cc, 60cc, 66cc, 70cc, and 80cc engines commonly used on motorized bicycles.The unit is constructed from laluminum alloy . TXT or email only I don’t answer unknown numbers thanks for your time MARTIN oh yea hole measurements 2 and a half X 2 and a half CENTER