Nilfisk GB933 and GB1033 Industrial Vacuum Cleaner Cotton Main Filter OBSOLETE
These filters are no longer available.
I've used a photo of the Goretex filter to show the length, for the main picture, whilst the third photo shows the cotton filter used in the Nilfisk GS83 and GM83
Fitting these filters can be quite difficult if the person fitting it, hasn't done one before.
At the moment, as postage is capped at a maximum of $20, maximise the saving on postage and buy some of the related parts below, such as dustbags and the other filters or a new hose or floor tool!