FYI, drive shaft needs to be 1 1/2" long to use the set screws, or 2" for u-bolt. Entire unit is 3 3/8" *(w) x 5 5/8" (h) x 2 5/8" (d - distance it protrudes from mounting surface). Very solid build and seems powerful. Only has full-open and full-close SPST switches (no angle feedback).