As you can see from the picture I have limited space between the back of my miter saw and the wall.  The dust collection adapters I could find didn't quite fit into that space.  So a quick bit of modelling and three test prints later I finally have an adapter that works for my space.

You're going to need supports for this one.  I've included a .3mf file that when loaded into Prusa Slicer should give you paint-on supports that worked for me.

I'm using this for a DeWalt DW703 miter saw but it should work for anything with a 1.5" dust collection port.  It's going to a 2.25" shop vac.  Yes, Rigid calls the hose a 2.5" hose but the actual measurement is 2.25".  I have no idea what they're trying to do there.