Household central ducted vacuum cleaner system short 50mm PVC 90 degree elbow for use close to switched flap valves.
These elbows are usually fitted near to the flap valves, where they come down behind the wall.
Incidentally, short elbows are fitted in this position, so they jam items like pens here at the flap valve outlets where they can be easily be removed because the bend is too small for long objects to get around.
As it's light, maximise the saving on postage and buy some of the related parts below, such as dustbags and the filters or a new floor tool.
At the moment, standard postage within Australia is capped at a maximum of $20!
We at TVD carry out in-home repairs on built-in ducted vacuum systems in the Perth area from $135, call 08 9362 6044