32mm backpack vacuum cleaners hose plastic click ring for hose bent tubes or hose cuffs.
They secure the white threaded Hull in place, with two dimples. Simply depress in the dimples with a screwdriver. They are also on cheaper barrel commercial vacuum cleaners such as the original VAX.
In the second picture, it's at the bottom of the photo. Same in the third picture. The white hulls and bent tube are NOT included. They are for illustration only.
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!
At the moment, standard postage within Australia is capped at a maximum of $20!