These are top quality pumps. Most important, they are Ethanol resistant. If your pumps have a black cup (rubber part), do not use them. They will only last a few weeks with Ethanol fuel. Additionally, you will note these pumps have the "garter spring" around the inside of the cup to help them last longer. And, they come assembled with a new spring and cap to hold the spring in place. These are the best pumps I can find. I use them in all my restorations.