It is waterproof？ I bought a set of patio furniture but a lot of compalins about the rust problem after one month use.

Rust-Oleum Stops Rust Crystal Clear Enamel will help block moisture from getting into the surface; however, it's not considered a water-proofing product. It sounds like you may have needed to go a little bit heavier with the application to ensure that air and moisture do not get to the metal causing premature rusting. This product does contain rust inhibitive properties and we are confident that if you apply it thicker, you'll have great results.