Sure you could use something else but I usually buy all the stuff to do it "right" then find its crap or it dont fit and still end up bodging!
with mine there was a gap ie they didnt fit!. Could have wacked some jubilee clips up tight I spose!!!
For my aircold T25 took an alternative route and bought some heat resistant silicone reinforced ducting off fleabay, then lagged it with some glass fibre ducting, not original but it is certainly flexible enough.
I brought the rubber connector things and they won't fit my 1600 so I had to take them off again. Waste of money