This is bipolar Nema 17 stepper motor with 1.8° step angle (200 steps.revolution). Each phase draws current 0.4A at 12V, allowing for a holding torque of 26Ncm(36.8oz.in). A rear shaft can mount encoder or equals.Electrical Specification* Manufacturer Part Number 17HS130404D * Motor Type Bipolar Stepper * Step Angle 1.8° * Holding Torque 26Ncm(36.8oz.in) * Rated Current.phase 0.4A * Phase Resistance 30ohms * Recommended Voltage 1224V * Inductance 37mH±20Percent(1KHz)Physical Specification* Frame Size 42 x 42mm * Body Length 34mm * Shaft Diameter ?5mm * Front Shaft Length 20mm * Rear Shaft Length 10mm * Dcut Length 15mm * Number of Leads 4 * Lead Length 400mm * Weight 230gConnectionBlack(A), Green(A), Red(B), Blue(B)WarningMake sure the motor connect to a constant current or chopper drive controller before you test motor. Connecting the motor directly to a power supply will destroy the motor.