My only Festool is the little hand sander you can hook a dust collector too. It has a valve for air control but that was not sufficient with my shop vac and 35mm hose hooked up. So I tried a speed controller for a router. Works GREAT. No problem dialing in enough air flow to get the dust without sucking the sander down so hard it's difficult to sand. I don't know much about Festool sanders but as long as they have a universal motor (brushes) it should work on them too. All you do is plug the controller into the power source and then the DC into the controller. There is a dial to control speed. Lower speed also means lower noise.