The 41A4252 belt drive gear kit uses a belt to drive the opener system as shown above. I used the parts numbers below use a belt like the one above.
Note: You must have a belt like the one above for this gear kit to work.
Belt Drive Units: 41A4252, 41A4252-6, 41A4252-6a, 41A4252-6b, 41A4252-6c, 41A4252-6d, 41A4252-6e, 41A4252-6f, 41A4252-6g
Belt Drive Units: 41A4252-1, 41A4252-5, 41A4252-7, 41A4252-7a, 41A4252-7b, 41A4252-7c, 41A4252-7d, 41A4252-7e, 41A4252-7f, 41A4252-7g