One end connects to the Bosch "Click and Clean" port (45mm internal diameter) on your mitre saw (or other Bosch tool) and the other end connects to a regular 60mm internal diameter hose from your dust extractor/vacuum.
Recommended to print in something flexible enough at narrow widths, but also rigid enough when printed with a wider width, like PETG (the lower part of the tabs have a width of 1mm and must bend to fit into the slots of the Bosch “Click and Clean” without snapping).
The author marked this model as their own original creation.