is capable of driving from size 11 through size 34 step motors. Model OFS350-DRI is drive-only version requiring step and direction inputs. Model OFS350-OSC has basic onboard control capability. Measuring only 4 x 3 x 1.5 in., drives have 3-state, PWM, MOSFET H-Bridge technology. Compumotor-brand Open Frame Stepper (OFS) microstepping drives deliver 3.5 A peak current/phase.