... .1.Features Of BF1 Clamp Type Flexible coupling with curved Jaw: * Coupling assembled by pressing a polyurethane sleeve into hubs ... of hollow shaft can be defined by user; Standard hole: Φ 4, Φ 5, Φ 6, Φ 6.35, Φ 8, Φ 10, Φ 12, Φ 15, Φ 20, Φ ... indicate)M: The hole dia. of the encoder end.Φ4,Φ5,Φ6,Φ6.35,Φ8,Φ10,Φ12,Φ15,Φ20,Φ25 ... , Φ30mmN: the hole dia.of the user end.Φ4,Φ5,Φ6,Φ6.35,Φ8,Φ10,Φ12,Φ15,Φ20,Φ25 ...