Jaw Coupling Hub, Coupling Size FC25, Outside Diameter 2 1/2 in, Coupling Overall Length 4 1/8 in, System of Measurement Inch, Hub Material Stainless Steel, Maximum Speed 3,450 RPM, Keyway Depth 1/8 in, Keyway Width 1/4 in, Bore Diameter 1/4 in, Shaft Locking Type Set Screw, Bore Type Round Bore with Keyway, Jaw Profile Straight, Screw Thread Size 3/8 In.001/-0.