A Nema 34 stepper motor is a stepper motor with 3.4 x3.4 inch(86x86 mm)face plate,Nema34 have 8 wire motors that can be connected in all possible configurations : Series,Unipolar,Parallel

A Nema 23 stepper motor is a stepper motor with 2.3 x2.3 inch(56.4x56.4 mm)face plate,Nema23 high torque stepper motors provide great value with no quality sacrifice

A Nema 17 stepper motor is a stepper motor with 1.7 x1.7 inch(42x42 mm)face plate,Nema17 size hybrid bipolar stepping motor has a 1.8' step angle(200 steps/revolution)

Nema 24 Step motor is Extra medium size motor with high torque