Nilfisk AX400 and AX300 and Advance Aquaclean Roller Brush Large Bearing Block
The photos are from a customers machine in for repair, to illustrate the part. In the main photo, it's the black item at 10 o'clock. Needless to say, you will get a brand new one when you order.
At the moment, as postage 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!