Fits standard Shop Vac or other common wet/dry vac 2.25in (57.15mm) hoses. I used it to add a dust collection port to an old table saw.
Holes are on a 3-5/32in (3.15in, 80mm) dia circle and are sized for ¼-20 bolts. Vac hose fits ID of flange.
The author marked this model as their own original creation.