The AirFlap46 is a two-piece set specifically designed to connect a 4 inch hose coming from your Glowforge to the AC Infinity Cloudline 6" Fan, and then to connect the outgoing end of the Fan back down to a 4 inch flex hose.
The 4 inch to 6 inch adapter of the set includes a built-in butterfly valve, thereby serving as both an adapter and air-flow shut-off point when fan is not in use, to protect your Glowforge from outside cool air.
(If you are interested in this set, however own a different fan requiring different dimensions, please request a quote by emailing us at 3DProdigies@gmail.com, provide your desired dimensions, and leave a name and phone number so we may contact you.)