THERE ARE 5 MAGNETS OF 5mm DIAMETER BY 1 mm THICK, EXTREMELY STRONG THEY ARE RARE EARTH NEODYMIUM OR NEODYMIUM USEFUL FOR INDUSTRIAL APPLICATIONS, ACTIVATION OF MAGNETIC CONTACTS, LIMIT SWITCHES, ETC. APPLICATION IN DIY AND VARIOUS CRAFTS. ALSO USED IN THE DETECTION OF COUNTERFEIT COINS FOR ITS ABILITY TO DETECT IRON CONTENT AND OTHER NON-PRECIOUS METALS