... N: The hole dia. Of the user end. * D and L can be defined by user; Standard: Outside D=50mm, length=55mm ... . * Diameter 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 ... indicate)M: The hole dia. of the encoder end.Φ4,Φ5,Φ6,Φ6.35,Φ8,Φ10,Φ12,Φ15,Φ20,Φ25, Φ ... 30mmN: the hole dia.of the user end.Φ4,Φ5,Φ6,Φ6.35,Φ8,Φ10,Φ12,Φ15,Φ20,Φ25 ...