This pretty snap says "Teachers Rule" for snap on jewelry.
Snaps are lightweight and interchangeable charms that will work with most, if not all, of your snap jewelry bases. Snaps are 7/8" in size (or about 20 mm). Snaps work with standard 18-20mm snap jewelry. How do you wear them? Select a base pendant, bracelet, accessory or key chain. Select lots of fun snaps. Pair, wear and enjoy!