Jaw Coupling Hub; 5/16" Bore; 5/8" Hub Dia; Jaw Coupling; Hub; Shaft; Finished Bore; No Keyway; 0.63" Outside Diameter; 0.27" Length Thru Bore; L035 Size or Series; Set Screw; Powdered Metal; 31000 Maximum Speed; Buna-N 3.5 | Urethane 5.25In-Lbs Torque