Dowierj, I have also used por 15 for a few years and it seems to work good. Word of caution follow directions , do not get on your hands ( is impossible to clean after it dries, has to wear off) and wear a good mask. I was spraying under an old truck one day and was outside. I just picked up the gun and started spraying realizing in a few seconds that I forgot to put on my respirator . I coughed up black crap for two days , my throat killed me and all because I was careless. That stuff will kill you . Darin