Generic Universal Air Mover 3 Speed Switch Assembly. Fits over 90% of the air movers on the market including Viking Equipment Mounting holes: 2 at 7/16" Diameter @ 1-7/64" apart. Switching knob is included! Switching knob needs a dab of glue after assembly to hold in place!!!!!!!!! Switching knob shaft passes through a 3/8" hole Standard .25 inch diameter shaft. Also marketed under part A955A Nilfisk Hydro Dry 5611504 Schematics of mounting Installation Instructions