The Starrett DB2 Debris Collector. Simply insert the arbor shank through the eyelet at the nylon base, press the rim of the cowl against the surface of the material being sawn and begin sawing.
The flange of the cowl then forms a seal against the material being cut, collecting all dirt and debris inside the cowl. Suitable for TCT Fast Cutting Multi Purpose and Bi-Metal Hole Saws up to and including 121mm (4.3/4").
"Absolutely brilliant. Just drilled six holes in the ceiling ready for new downlighters to be installed. No plaster dust whatsoever, all caught by the debris collector. Wish I had bought one of these years ago. At first I thought it was a bit expensive, but when it works so simply and so effectively I can't recommend it highly enough"