I would like to know the exterior diameter of the vacuum end (the end that plugs into the vacuum) of the D27 Antistatic hose, Festool Product No. 452878. I am considering the addition of a Domino DF500 to my shop equipment, but since I already own 2 excellent Fein Vacuums, it would have to marry up to one of these existing vacuums. The Fein vacuum has a intake port that measures 2-1/4 in. If it is any help, the hose for the Mirka sander that I recently purchased fit the Fein Vacuum perfectly. If it not 2-1/4 inches, does Festool offer an adapter to this vacuum?