La Pavoni Sightglass Nut Chrome If you are replacing plastic sightglass nuts, you will need to add the metal washers. Note: On very old Pavonis, the sightglass and gaskets were a different size. If you are replacing either item on an older unit which came with the metal sightglass cover, then we recommend replacing the glass, gaskets, and, if your unit did not originally come with them, adding the metal washers.