Sprocket has 9 holes evenly spaced around the sprocket. The center diameter of this sprocket is 5 7/16 of an inch. The models that use this sprocket are Sherpa T models 156, 158, 159, 182, 183, 185, 190, 191, 198A, 198B,199,199A and 199B models as well. The Pursang models are 162, 170, 194 and 200.