Yes, their sealant is the only one I'd ever trust on a fuel tank. It's a permanent solution used across the board for all sorts of fuel tanks by a lot of restoration shops. The cleaner and prep solutions in the kit are "meh". It's a nice all-in-one rusty tank kit for under $60 tho. Get a 5gal bucket of evapo-rust and dunk the entire tank and let it sit overnight. It works far better and is cheaper, same phos acid solution from what I can tell.