Rust Check is a unique formula that penetrates into every crevice and seam of your vehicle, actually bonding to metal to displace and lock out moisture in critical rust prone areas. this is especially important with today's uni-body construction. Rust Check is "Guaranteed Forever" on new and qualified used vehicles when treated annually. for about the cost of four annual engine oil changes you can protect the structural integrity of your vehicle with Rust Check. more... See more text