NEMA 17 – 12V – four-phase unipolar permanent-magnet stepper-motor
1.8° full step – 200 steps-per-revolution
0.9° half-step – 400 steps-per-revolution

NEMA chose to label stepper motors (e.g. “NEMA 17”) with the size of their faceplate in tenth of inches. So a “NEMA 17” has a 1.7 inch by 1.7 inch faceplate. By standardizing the stepper motors (the faceplates, flanges and screw holes), you know ahead of time that one NEMA 17 motor will fit into the mounts of another NEMA 17 without having to redesign anything. This makes swapping components easier.

42BYGH34
1.5 kg-cm 6 Wire NEMA 17 Stepper Motor – Item no. 42BYGH34-04
12VDC, Rated current 1.3A, 500rpm, Torque 0.26NM, size: 42x42x34mm

17HS1352-P4130 – hybrid
2.2 kg-cm 6 Wire NEMA 17 Stepper Motor
12-24VDC, Rated current 1.33A, 500rpm, Torque 0.26NM, size: 42x42x34mm

42BYGHW609D4P-X1
1.7A – 1.8degrees

42BYGHW609D4P1 Stepper Motor (Makeblock 81042)
Specifications
PHASE : 2PHASE
STEP ANGLE : 1.8+-5%°/STEP
RATED VOLTAGE : 12V
CURRENT : 1.7A/PHASE
RESISRANCE : 1.5+-10%/PHASE
INDUCRANCE : 2.8+-20%mH/PHASE
HOLDING TORQUE : 40N.cm Min
DERENT TORQUE : 2.2N.cm Max
INSULATION CLASS : B
LEAD STYLE : AWG26 UL1007
ROTOR TORQUE : 54G.cm2