This is an updated version nema 17 stepper motor with holding torque of 59Ncm(83.6oz.in). It's good for 3D printers, as well as CNC and robotics applications. Electrical Specification: - Manufacturer Part Number: 17HS19-2004S1 - Motor Type: Bipolar Stepper - Step Angle: 1.8 deg. - Holding Torque: 59Ncm(83.6oz.in) - Rated Current/phase: 2.0A - Phase Resistance: 1.4ohms - Inductance: 3.0mH+/-20%(1KHz) Physical Specification: - Frame Size: 42 x 42mm - Body Length: 48mm - Shaft Diameter: 5mm - Shaft Length: 24mm - D-cut Length: 15mm - Number of Leads: 4 - Lead Length: 1m. - Weight: 390g Connection: Black(A+), Green(A-), Red(B+), Blue(B-) Warning: Connecting the motor directly to a power supply will destroy the motor.