Its really good but nothing protects against salt eventually - Even ACF50. I personally avoid using on electrical connectors, have heard of a few probs there - many swear by it, as do manufacturers - your call.
But one head up's from your resident industrial chemist... The safety sheets for this stuff don't do it justice. They just talk about eye safety.
I use gloves, glasses, washable overall and apply in well ventilated area and don't breathe the smoke when it burns off. (likely sulfuric, nitric acids among a host of others). Whilst the liquid and aerosol formulae differ, ACF is essentially a Naptha solvent, and something classified in American as "hydrogenated neutral oli" - but in English we call
"Lubricating oils (petroleum), C20-50, hydrotreated neutral oil-based".
This is mix of really long chain hydrocarbon oils+waxes left over from the fractional distillation process from crude. Its hydrogenated (like margarine) to produce more saturated chains. Oh and the heads-up - Its a Class 1B mutagen. Any container of it would have to have the carcinogen label and "May Cause Cancer" in clear lettering. Its 70% of the formula and 100% when its dried on. So wash it off first!!
Naptha's fairly safe unless you drink a can, likewise the 1,1-difluoroethane in the aerosol version unless you sniff the whole can. (good luck with that).
Why it works? Not my area of expertise (lubricants) but here's my guess/
Its an oil, and very water repelling, especially the longer chains which are more wax like than oil like. The C20-50 oil is high viscosity and I'm guessing really crap flow properties meaning it sticks well to the parts coated and won't 'run-off easily'. The hydrogenation process creates Lots of saturated double bonds, meaning this oil oxidizes/peroxidizes very quickly once it gets going - and catalytically so in the presence of metals. Hence this acts as a 'corrosion sink'.. The oil coating gets super oxidized and rancid (like off butter) as a sacrificial oxidizing agent. Any Oxygen would rather react with the oil than the metal it coats and before the oils is spent oxidizing you have probably washed it off and re-applied.
Everything else is a solvent.
Genius.
PS saftey data sheet here
http://www.acf-50.co.uk/acro2017/10013%20ACF-50%20%20AEROSOL%20MSDS%20_%202017%20_%20ENGLISH.pdf