Festool Dirt Trap 452925 for the CT22.

I use the dirt trap when I'm going to produce a lot of saw dust or larger chips, like from my jointer or form bigger router bits. First I switch the HEPA filters out for the non HEPA ones (part #452923). Then I remove the filter bag. Pictured below.

With the bag out, drop the basket in and fit the top, line up the openings and press in.

Once the basket is full, you dump it out and reinstall it quickly.

Two things to keep in mind when you use the dirt trap, first, it will shorten the life of the filters if you use it this way, that's why I use the non HEPA filters. Also, it will make much more of a mess inside the vacuum, just like a shop vac, so I clean mine out once in a while with my mini. This approach saves my from going through a lot more filter bags.