What is this?Magnetic stir bars are used to stir liquids or solutions in the biology and chemistry field, research laboratory applications, etc. Usually used with a magnetic stirrer or heating stirrer, quieter, more efficient than other stirrers.What will I get?The magnetic stir bar is in size of:Total length: 20mm(0.79 inch); Diameter(Approx): 8mm(0.31 inch);In the package of: 4 x Magnetic stir barAre there any advantages of the product?The magnetic stir bar made from magnet with PTFE coating, the coating is corrosion resistant and has good resistance to high temperature(temperature tolerance range:-180 ℃~250 ℃), smooth surface, reduce friction and improves smooth rotation, easy to clean. with Ring shape, more suitable for flat-bottomed containers, with better rotational stability and better stirring effect. What should I notice?Please place the magnetic stir bar in the bottom center of container when use.The magnetic stir bar is reusable, please wash and dry it after use for next time use. Keep away from iron and other magnetic materials, so as not to affect the magnetic properties of the magnetic stirrer. It should be replaced when the appearance of the magnetic stirrer is obviously worn, or the magnetic force has faded seriously