Magnetic Stir Bars High Magnestim PTFE Coated by Duda Energy Magnetic stir bars are used with magnetic stirrers for stirring liquids. These stir bars are PTFE (teflon) coated and appropriate for most chemistry applications. The PTFE is highly resistant to corrosion from chemicals. They work well in Biodiesel Titrations and test batches. High Magnetism Our stir bar magnets are rated with 2000-3000 gauss. High magnetism ensures good stability and control when using with a magnetic stirrer. The Different Types of Stir Bars: Standard: Standard stir bars are in the shape of a rod. They are for general stirring applications. Standard with pivot ring: Standard stir bars with a pivot ring are used to reduce friction. The pivot ring allows the stir bar to rotate on the ring only, making the stirring more efficient. The pivot rings are most useful when stirring liquids in a container which is slightly curved or has an uneven base. Oval Stir Bars: Oval stir bars are for containers which have curved or round bottoms. The unique shape maintains stability even at high speeds. Star Stir Bars: Star stir bars have the most stable stirring, great for high speed stirring. Stir Bar Retriever: Use stir bar retrievers to retrieve stir bars from a liquid solution. PTFE coating and a strong magnet on the end allows for easy removal of stir bars in solutions.