Great For Auto Restoration, Floors, Chassis, Trunk, Etc... Stops Rust 1 Quart Paint right over rust on floor pans, frames, chassis components, or anywhere you see rust developing. Por - 15 is the toughest rust coating available. So tough after applied it will not crack even under the impact of a hammer. Por - 15 is not affected by salt, gasoline, or oil. Por - 15 stops the rust from reaching the base metal. This must be shipped via ground service.