5 Magnetic stirrer bars Length: 20mm, Thickness: 6mm Colour : White (With blue hue) Teflon (PTFE) casing is chemically inert, can be used with corrosive chemicals, and helps reduce friction and wear while spinning Built-in pivot ring helps reduce vibration and wear during stirring Internal magnet made from alnico V, an alloy of aluminum, nickel, iron, and cobalt.Magnetic stir bar with built-in pivot ring has a white Teflon (PTFE) casing and an internal magnet made from alnico V (an alloy of aluminum, nickel, iron, and cobalt) for a range of laboratory stirring applications. The magnet sits inside a Teflon (polytetrafluoroethylene, or PTFE) casing, which is chemically inert, can be used with corrosive chemicals, and helps reduce friction and wear while spinning. A built-in pivot ring minimizes contact between the bar and the container to help reduce vibration and wear during stirring. Magnetic stir bars (sometimes called stirring bars, spin bars, or fleas) are used to stir a liquid or solution in biological, chemical, medical, and research laboratory applications. The stir bar is placed inside a container of liquid or solution that is seated on a magnetic stirrer (also called a magnetic mixer), which is a laboratory device that creates a rotating magnetic field using a rotating magnet or multiple stationary electromagnets. The rotating magnetic field causes the bar to spin, which stirs the liquid or solution. Stirring bars are offered in a variety of sizes and shapes, and they are encased in materials such as glass or plastic to help prevent contamination of the liquid or solution, to reduce friction, and to provide resistance to chemicals, abrasion, and heat. The bar may have a pivot ring or pivot point to minimize contact with the container, reduce friction, and improve its spinning. The size and shape of the container and the volume and viscosity of the liquid or solution to be stirred determine which stir bar shape, size, and casing will suit a particular application.