Part No.  39BYG003Single Shaft Frame Size NEMA16 Step Angle:  1.8 degree Voltage:  12VDC Current:  0.48A/phase Resistance:  25Ohm/phase Inductance  22mH/phase Holding torque:  100Kg-cm Rotor inertia:� � � 11g-cm2 Detent torque:� � � 5kg-cm Number of wire leads:� 4 Weight:� � � 0.12KG Length:20mm Front� shaft� diameter: 5mm Front shaft length:� � 24mm round shaft This model is for Single shaft, with 5mm motor shaft, 24mm front shaft length, round shaft! More Order Quantites, more  discount!