16mm inside diameter snap bezels
These are the snap bezels I use for my 15mm lampwork glass cabochons. They measure 16mm inside, and 18mm outside, and fit all of the snap jewelry compatible with Noosa and Ginger Snaps. They do not tarnish or rust. Simply epoxy your glass cabochon inside and you're done. They also make very nice bezel trays for resin creations, as shown in the second image.