These thick gel rings are a fantastic upgrade over the standard vinyl-coated foam pads that most Peltors come with from the factory. Better seal, more stability, and the fact that these don't freeze and lose their flexibility are huge benefits both for comfort and safety!
Installation is easy, just pry the old pad rings loose (use a regular table knife if you have to) and snap the new ones in! You should hear and feel a click when the rings lock in properly. Fits (at least) the Comtac XP and XPI models.