Hose Adapter doesn't fit any of my vacuum hoses and doesn't come with any spacers or adapters allowing the vacuum hoses and hose adapter fit together and work. You end up duct-taping the hose onto the adapter which doesn't work well and is gets in the way. Waste of time and money, don't bother unless you can machine your own hose/adapter to make the two work together.
I have a really old (and worn out) Bosch orbital sander and a much newer model also from Bosch (that matches the selection criteria for this adapter). My dust collection hose from the old sander with a round port works fine with the adaptor for the new sander with the slotted port. This provides a vast improvement in keeping my shop dust free.
This adapter easily connected to my new Bosch 5" Electronic Variable Speed Random Orbit Sander/Polisher and my Fein vacuum hose easily connects with no issues at all. This is the best performing Bosch connection in what is now my third version of the 5" RAS.