The Nilfisk BA755ST and Advance Warrior battery operated floor scrubber 370mm abrasive pad holder, two are needed for a set, and the are supplied with the locking device disc with the stainless steel spring clip.
Although 370mm abrasive pads should be used, most people will use the 350mm ones that are commonly available. 370mm pads can be ordered though for customers who don't mind the wait and extra price.
At the moment, standard postage within Australia is capped at a maximum of $25 so maximise the saving on postage and buy some of the related parts below!