Key lock for the cylindrical microfibre roller, and brush for the Nilfisk SC100 walk behind automatic floor scrubber drier this locks the scrub brush in place.
The microfibre roller is shown in the second photo, this does not come with the key lock.
At the moment, standard postage is capped at a maximum of $30 within Australia, so maximise the saving on postage and buy something in the related parts below!