Magnum Magnetics-Corporation ProMAG Round Ceramic Magnets, 3/4" 2 pack Grade 5 Ceramic Disc Magnets are strong and measure 11/16 Inch (.709" or 18mm) Round x 3/16" (.198" or 5mm) Thick Great for all home, office, craft, hobby, science projects and product manufacturing applications. Magnets are perfect for glass gems, mirrors, for making refrigerator magnets, and more others. Highly stability under difficult environment conditions with no need for a coating to protect the magnet. Pack of 104 pieces for one low price!