We have just checked with the manufacturer and they have said they are roughly 1 metre each.
These Replacement Tubes are for a 6 Litre Vacuum Oil Extractor i would not think you could use them for a 8 Lite Vacuum Oil Extractor.
I am very sorry, we do not sell the dipstick one on its own, only in this set.
The outer diameters are 35mm, 18mm and 16mm.
We are not able to source the bag separately