Chain Coupling Sprocket, Chain Number 40, Bore Diameter 1 1/4 in, Bore Type Round Keyed, Horsepower @ 100 RPM 4.14 hp, Outside Diameter with Chain 3 in, Hub Diameter 1 3/8 in, For Chain Pitch 1/2 in, Keyway Depth 1/8 in, Keyway Width 1/4 in, Maximum...