Rust-Oleum Stops Rust auto-mobile primer provides a durable rust inhibitive base for most automotive lacquers and enamels. For maximum protection, top-coat with a Rust-Oleum Stops Rust enamel. If using an auto-lacquer, a test application for compatibility is recommended. Stops Rust auto-mobile primer features a comfort tip with a wider finger pad to reduce fatigue caused by continuous spraying and the any-angle tip which allows you to spray at any-angle. Auto-mobile primer is fast drying and sandable for bare or lightly rusted surfaces. Not for use on galvanized steel.