Por 15 vs. KBS Rust Seal

One thing that confuses a lot of people is UV protection. There are two different UV ratings

• UV Stability
• UV Block

UV Stability refers to whether UV light will damage the coating
UV Block is how much UV light will pass thru the coating.

Products that lack 100% UV stability need a top coat that offer both 100% UV Blocking and are 100% UV stable if it's going to see direct sunlight.