Undercoating In A Can Black Wax Coating is a rust preventative/rust-proofing sealant. It is a wax based coating that is cutback with a solvent that assists in a quicker drying time than you would normally find with similar coatings that are cutback with water. 

Undercoating In A Can Black Wax Coating is designed to provide the ultimate protection for the under-body of automobiles, trucks, trailers and other transportation equipment. This is a black wax product that will become firm and dry to the touch but will not become hard. 

The benefit of this type of pliable self-healing coating is that it provides outstanding chip resistance. It is also a "Rust Encapsulating" coating which mean it can be applied over light rust and will stop further deterioration.