Designed as a print-in-one part for allowing a Dyson cordless vacuum to be used for dust extraction as a shop vac (eg as a lighter-weight alternative for extracting dust while sanding paintwork etc) or used to connect standard vacuum accessories.
The STL contains an example adapter for a 35mm (outer diameter) shop vac attachment. Still, the below Onshape link allows full and easy customisation (via parameters) of the adapter diameter/length for any other size:
The author marked this model as their own original creation.