This model is economy non captive stepper motor which named Nema 8 non captive linear actuator, the motor part is 30mm 1.8 degree 0.5A Nema 8 stepper motor. It was integrated with 100mm Tr3.5 threaded rod.  
Electrical Specification : 
Manufacturer Part Number: 8HY001-100T35
Motor Type: External Linear Stepper
Step Angle: 1.8 deg
Holding Torque: 15mN.m 
Rated Current/phase: 0.5A
Phase Resistance: 3.2ohms
Voltage: 3.2V
Inductance: 2.0mH ± 20%(1KHz)
 
Physical Specification : 
Frame Size: 20 x 20mm
Body Length: 30mm
Lead Screw Length: 100mm（3.937"）
Lead Screw Diameter: Φ3.5mm
Lead /Step: 0.61mm
Lead/Revolution: 0.61mm
Number of Leads: 4
Lead Length: 300mm
Weight : 150g