MSR Duraseal Pump Plunger Assembly (Pk of 5) Description: The plunger is the whole plunger unit including washer, complete with a new one piece collar that holds it into the stove. Most people who replace this do so because they have an old style two part collar which has an annoying habit of falling to bits now and then. The plungers are common to all stoves, ie a Dragonfly, XGK, and Whisperlite of the same vintage take the same plunger. There are four types of replacement plunger – it is important to get the correct one as they are not interchangeable. They are:Duraseal: The new pump introduced in 2004 (418809).