First, the drilling dust nozzle was designed as an accessory for the BHC 18 and PDC 18. It will work with other drills, but that was the original intent
As for drill sizes, it is designed for up to 12mm bits. Roughly 1/2". I'm in our Georgia rental, away from my home shop in Florida, but being the fabulously smart guy I am and a former Boy Scout ("Be Prepared").... I happened to have brought the Dust Nozzle with me!
(Purchased last year in Germany)
I have used the nozzle with my T18, PDC 18 and BHC 18, and it performs brilliantly. And YES... it WILL work with up to a 1/2" Bit!
.... And maybe just a hair larger.
Here's a picture of the nozzle with a 1/2" bit in it... and it's still pretty loose.
It's not designed for use with spade bits or forstners, but it works exceedingly well for collecting waste with bits up to 12mm/1'2".