NilfiskCFM 70mm black rubber connecting hose sleeve for the A17 compressed air industrial vacuum cleaner.
In the first photo, it's the "straight" cuffs, either side of the centre "waisted" cuff, which is Pn. Z7-20310
This straight 70mm black rubber sleeve fits on the short hose Pn. 40000592 connecting the compressed air powered air mover, to the primary or main filter chamber on top of the main unit. There is a hose clip, or Jubilee clip on the air mover end.
It's usually used on the compressed air driven NilfiskCFM A17 vacuum cleaner.
At the moment, as standard postage within Australia, is capped at a maximum of $20, maximise the saving on postage and buy some of the related parts below, such as dustbags and a new hose, or a new floor tool and some other accessory!