This is a selection of 3 Antique Canning Fruit Jar Covers or Insert Lids. One is a Aqua Blue insert that goes into a metal band (not included) It is marked MASON'S IMPROVED. The center has a Maltese Cross marked H F J CO. It measures 3 inches across. I found “The Maltese cross, in Italy also known as the Amalfi cross, is the cross symbol associated with the Knights Hospitaller (the Knights of Malta) and by extension with the island of Malta.” The other two are similar but not marked. They are not perfect. There may be a little roughness from storage and stains while there are no noticeable chips or cracks. Some of the wavy glass areas look like cracks. They have bubbles in the old glass. One may have roughness around the edge seam from the glass making mold. There is also some wavy lines in the glass indicative of old age glass. There are differences in coloring from green to blue and both sets are slightly different from aging.