I had the slip on one but I like this one so much better. Not only is it a period correct factory design, around the heat especially with headers and chemicals in engine compartment this seems so much more durable. These are heavy spring wire and really clamp down seal and seal cover. Takes some effort to snap in down into place. You won't have shrinkage or vibration loosening it like a slip on cap that has grease under it. I didn't even bend the tabs down on mine, the clamp holds it so tight.