NilfiskCFM 70mm container inlet, steel reducer to hose with 50mm internal diameter.
This part fits in the inlet to the NilfiskCFM127 and the NilfiskCFM137 and the NilfiskCFM SOL3 and the NilfiskCFM SOL5 and the NilfiskCFM S2 and the NilfiskCFM S3 and the NilfiskCFM T22 and the NilfiskCFM T40 and the compressed air driven NilfiskCFM A17 and several other NilfiskCFM vacuum cleaners.
In the picture, it's the centre part, as photographed, a 50mm steel hose is directly connected to it in this case.
In the second picture, it's seen coming out of the container and the 50mm hose is connected to it via a rubber 50mm cuff.
At the moment, as standard postage within Australia, is capped at a maximum of $20, maximise the saving on postage and buy several Puregiene toilet rolls a box of Tissues and some soap or maybe some packets of dustbags, or a hose or a new floor tool, or some other accessories!