Pipe 2.5 (F) to Festool D36 (M)
2.5 (in) Pipe Fits: POWERTEC 70176V Clear PVC Pipe 2-1/2"https://www.amazon.com/dp/B09NKWPT1C
Broadly speaking I hate this pipe as it's a non-standard size and their fitting are poorly labeled and designed to minimize cost while hurting their performance. ...But, it's a fair bit cheaper than PVC of similar diameter.
Festool D36 Fits: Festool's VACUUM PORT (The large, round end one would attach to the Vacuum/Dust Extractor) Hoses. Tested with Festool 204924 Extractor Hose D 36.
https://www.amazon.com/gp/product/B07VGN5TQZ
Design follow's manufacture's practice of employing an opposing taper- at some point those two cones will intersect- which should be more dimensionally tolerant.