This is just repackaged stuff with "professional, cycle ..." on it and sold at an inflated price in bike shops, just like "cycle" lubes and grease.
There are plenty of non-cycle rust proofing products that does the same thing if you want to use a specialised product rather than machine/engine oil/WD40 etc.
Eg, Waxoyl, available practically anywhere, £9 for 400ml, £20 for 2.5 l.
Framesaver, probably only a handful of places in the UK has it. The only online price I've found quotes £16 for 135ml (£7.50 P&P), and a 2006 review says £10.
Edit
I've read that Waxoyl is quite thick and needs to be warmed or thinned with a solvent, Dinitrol is supposed to be thinner.