Ace Rust Stop is a special rust inhibiting primer formulation that protects iron and steel from rust corrosion. Bonds tightly to metal to seal and protect for long lasting protection. Prevents rust. Weather resistant. When applied on properly prepared metal, this primer slows or stops rust from crawling under the paint film. Excellent for protecting equipment. Use on light fixtures, patio furniture, mailboxes, and more. For ferrous metal substrates (bare, painted, or lightly rusted).