Einhell TE-RS 18 Orbital Sander to 1-1/2" Vacuum Hose Adapter

This adapter was designed to connect the bag port to a 38mm dust extractor hose (1-1/2" for the Americans). The dimensions are:

Sander-facing side: 40.5mm tapering down to 38.7mm over a 25.0mm distance
Hose-facing side: 39.0mm tapering down to 37.1mm over a 30.0mm distance

Please check your vacuum hose with calipers to ensure the outer diameter falls between the tapered widths. It should fit most but outer dimensions can vary a lot between hoses that are all marked as 1-1/2".

The fit should be snug enough that you don't need to hold it in place while using the sander, on both sides.