I heard about it on another website as a product to hide the sanding/grinding highlights on steel, so I bought some in various colors. It comes in small tins that look a lot like shoe polish and like polish, you can apply it with your fingers, a cloth, or brush. It acts more like a stain than a paint, but I think polish is closer to the way it really acts. It will cover the metal, dry, and then you can buff it out to a nice shine or leave it flat looking. The manufacturer recommends using a UV resistant clear coat after it's dried for durability and protection. It's supposed to leave a pretty good protective coating and of course whatever clear coat you use will improve that. You can put it on cold metal or metal that's not too hot to hold onto bare handed. If you spread it on the metal then wipe it off with a cloth immediately, it will fill in and color the low spots leaving the high spots untouched. I've used an old brush to really rub it into the cracks and crevices, let it dry, then buffed it and come up with a really nice sheen of whatever color it was. It comes in metallic colors as well as black, red, green, etc. It's another way to finish or color metal.