John Deere mower cutting unit splined coupling, 9 spline to 11. Fits the following models:

2243, 2500, 2500A, 2500B, 2500E, 2653, 2653A, 3215, 3235, 3215A, 3215B, 3225B, 3225C, 3235A, 3235B, 3235C, 7500, 8500, 8700