Hold blueprints, calendars, important memos, visual aides, work plans and more with these convenient, heavy duty magnetic bases. Ideal for warehouses, workrooms, offices and in the classroom. Each magnet features easy-grip knob for positioning and non-scratch liner to prevent marring. More About Ceramic Magnets: Our hard ceramic ferrite magnets are composed of iron oxide and barium or strontium carbonate. Ceramic magnets exhibit relatively good holding strength for their price, making them a popular choice for many consumer, commercial and technical applications. Ceramic magnets have so many practical uses including; craft projects, refrigerator magnets, badge holders, latches, display boards, loudspeakers, security systems, motors, generators & alternators, lifting magnets, brakes, clamps, switches & relays, sweeper magnets, science projects, toys, games, motors, magnetic couplings, POP displays, advertising giveaways, promotional items, novelties & much more.