This replaces the plastic part on the dust bag of my Dewalt saw. It broke on me years ago, so I didn't have all of the plastic part anymore, but i think i figured it out. This saw is over 10 years old so I guess it has their older style of dust connector. New bags cost about $15 and generally require an adapter as they are made for the newer style. This will cost you about half a dollar of filament. Now I can stop spraying so much dust all over!

The pictures should show pretty well how this put on. 

Turn the bag insided out.

Cable tie as shown and flip the bag back to outside out.

Notes:

No supports needed. It should load up in the intended print orientation.

I suggest 3 perimeters - mainly so the main tube part prints solid. I used petg for mine, but pretty much any filament should work.