I bought it for the wrong purpose. I have a custom air cleaner cap on my Firebird and it has an unused hole in the side for a tube. It was badly plugged by the previous owner and luckily I saw on a car forum that someone used those exact master cylinder seals to plug the hole. I decided to try my luck. I bought the package, removed the ugly plug and one of them just popped right out of the hole and sealed it up, looked a lot more professional and obviously just better looking. So for me +!