... rotational characteristics. * Material: Aluminum alloy + middle part: polyurethane 6 pieces. * M: The hole dia. Of the encoder end. N ... 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 25, Φ ... the hole dia.of the user end.Φ4,Φ5,Φ6,Φ6.35,Φ8,Φ10,Φ12,Φ15,Φ20,Φ25, Φ30mmTorque≤ ... ,Coupling ,Encoder coupling With Curved Jaw 6 Pieces ,BF1 Series (IBEST)