Arctic Cat Snowmobile Used Bottom Sprocket. Part # 0107-513. 

Fits the following models:

1976 ARCTIC CAT Cheetah 440 - DRIVE TRAIN
1976 ARCTIC CAT Panther 440 Fan Cooled - DRIVE TRAIN
1977 ARCTIC CAT Cheetah 500 Fan Cooled - DRIVE TRAIN
1977 ARCTIC CAT Pantera 500 Fan Cooled - DRIVE TRAIN
1977 ARCTIC CAT Panther 440 Fan Cooled - DRIVE TRAIN
1977 ARCTIC CAT Panther 500 Fan Cooled - DRIVE TRAIN
1978 ARCTIC CAT Cheetah 500 Fan Cooled - DRIVE TRAIN
1978 ARCTIC CAT Pantera 500 Fan Cooled - DRIVE TRAIN
1978 ARCTIC CAT Panther 4000 (440) Fan Cooled - DRIVE TRAIN
1978 ARCTIC CAT Panther 5000 (500) Fan Cooled - DRIVE TRAIN
1979 ARCTIC CAT Pantera 500 Fan Cooled - DRIVE TRAIN
1979 ARCTIC CAT Panther 500 Fan Cooled - DRIVE TRAIN
1980 ARCTIC CAT Pantera 500 Fan Cooled - DRIVE TRAIN
1980 ARCTIC CAT Pantera Electric Start 500 Fan Cooled - DRIVE TRAIN