This item includes:

4pcs  4-lead Nema23 stepper motor 425oz.in with dual shaft. 

        length of front axle 21MM,diameter of front axle 8MM

        length of back axle 15MM,diameter of back axle 6.35MM

stepper motor ---23HS2442B

Part No.:                                    23HS2442B

Frame Size:                               NEMA23

Step Angle:                               1.8 degree

Voltage:                                     3.36V

Current:                                     4.2A/phase

Resistance:                             0.8 Ohm/phase

Inductance:                               3.7mH/phase

Holding torque:                        3.0N.M    ( 425OZ-IN )

Number of wire leads:             4

Weight:                                       1.7 kgs

Length:                                     112mm

Front Motor Shaft:                    8mm

Front Shaft length:                  21mm

Back 

Motor Shaft:                            6.35mm

Back Shaft length:                  15mm