#25 Roller Chain Sprocket 04C 9T-40T Tooth Bore 5mm-20mm Pitch 6.35mm (1/4 inch) RM 13.64 to RM 53.35
#25 Roller Chain Sprocket With Keyway 04C 13T-40T Tooth Bore 8-30mm Pitch 6.35mm RM 20.54 to RM 59.91