Sprocket 415 B 10 Tooth 5/8" ID with a 3/16" key way, two set screws.
We took a # 41 sprocket and milled down the teeth to make a 415 that will use 1/2" x 3/16" chain.
Best to use 415 chain (1/2" pitch x 3/16" width) These sprockets can also be used with #41 Chain (1/2" x 1/4") and #40 Chain (1/2" x 5/16")