Use a CF (Can Fan, Can Filters) flange to connect your exhaust fan to your fan filter. 

Find your filter size below to match to the Can Fan Flange size.

4" CF Flange:

Inside diameter = 4"
Outside diameter = 5.5"
Fits Can-Filter 2600 or 9000

6" CF Flange:

Inside diameter = 6"
Outside diameter = 11.75"
Fits Can Filter 33, 66, 50 or 99

8" CF Flange:

Inside diameter = 8"
Outside diameter = 11.75"
Fits Can Filter 50, 66, 75, 99 or 100

10" CF Flange:

Inside diameter = 10"
Outside diameter = 14.75"
Fits Can Filter 100, 125 or 150

12" CF Flange:

Inside diameter = 12"
Outside diameter = 14.75"
Fits Can Filter 125 or 150

14" CF Flange:

Inside diameter = 14"
Outside diameter = 19.5"
Fits Can Filter 125 or 150

Some Can Filters are able to use 2 different sizes of flanges. Choose which will work best for your application.