This is a pack of 10 magnetic stir bars made from ALNICO one of the strongest permanent magnets available.The sintered manufacturing process reduces the chance of decoupling (spin outs) which weaker stir bars often suffer from.Encapsulation in PTFE protects both magnet and what it is stirring. Chemically inert and easy to clean.Can withstand temperatures up to 250°C making them suitable for use with both unheated and heated stirrers.Low friction octagon shape with a centre pivot ring helps create a strong mixing vortex even with more viscous solutions.The stir bar retriever (B8R02602) can recover stir bars even in hot solutions when stirring and mixing is no longer required.Octagon ShapePTFE Coated(L)20mm x (W)8mmPack of 10