These plugs have a cork gasket as opposed to the rubber o-ring. I find the rubber o-ring more durable. Thus, I bought other Hayward flush mount plugs with the traditional rubber o-ring. I'll use these in the overflow line when the pool is open so I can monitor them. I also did not winterize using these. Get the Hayward non flush mount with the rubber
o- ring for winterizing. Easier to install. More durable.