The KBWM control is a compact version of our Multi Drive (KBMD). The control is packaged in an all metal NEMA-1 enclosure. This unidirectional SCR drive utilizes the KBMM speed control module which prevents motor failure due to demagnetization and contains AC line and armature fusing and a barrier terminal connection block. The KB Plug-in Horsepower Resistor? automatically calibrates IR Comp and CL.Dimensions:3.70" x 6.80" x 3.00"