Fluid film rust treatment

I'm in pa and use it on my truck every fall. 04 ram with no rust. I buy it by the gallon and use an undercoating gun. I also buy a few cans to use my spray tubing in all the nooks and crannies. Takes about 2 hours. I only clean the painted body surfaces during winter and do nothing with the wheel wells or underside until spring. It does smell for a week or two after applying and when the moisture or condensation drips off it makes it appear to have a fluid leak. All worth it to me to have a truck notorious for rust being rust free after 18 years.