Simply awesome!  This sprays on like a thinner oil, creeps into cracks, seams and rust, then thickens up as it sits.  The final protection is a waxy/heavy greasy film.  Spray in layers where added protection is needed.  Obviously this won't stop or reverse rust damage, but it does wonders at halting the rust in its tracks.  I use this on my classic cars to stabilize rust damage, and for this the product does an excellent job.  The only thing I wish was better was the nozzle.  It comes with a fine misty type nozzle, but for my purposes I change this out for a nozzle with a spray tube.  With a spray tube nozzle in place this can be shot deep into hard to reach places.  Other than the nozzle, the product itself works very well.