The Magnetic Stir Bar is a required accessory for your laboratory stir plate. This stir bar is coated with PTFE for superior chemical resistance, and contains an Alnico magnet for use with most stir plate drive magnets. The pivot ring in the center of the stir bar spins smoothly and evenly, and the magnetic stirring action vastly improves the consistency and purity of solutions over long periods of time compared to manual stir utensils. This stir bar measures 1.8″ (48mm) long and 0.5″ (12mm) in diameter.