Info:Martin 200A20 Type A Single Strand Solid Reboreable Roller Chain Sprocket, 1.5 to 13.254 in Dia Bore, 17.284 in OD, #200 Chain, 20 Teeth, 2-1/2 in Pitch, Steel
Info:Martin 200A21 Type A Single Strand Solid Reboreable Roller Chain Sprocket, 1.5 to 14.056 in Dia Bore, 18.086 in OD, #200 Chain, 21 Teeth, 2-1/2 in Pitch, Steel