Features Including: There are 7pcs Stir Bars, made of PTFE material, resistant to high and low temperature, strong acid, strong alkali, various organic solvents, and the quantity meets the basic daily use needs. Size: Length*Diameter are 10mm*4mm, 15mm*6mm, 20mm*6mm, 25mm*7mm, 30mm*7mm, 35mm*8mm respectively. Use: These stir bars with strong practicability can be widely used with various types of magnetic stirrers or heating stirrers, with strong magnetism, accurate size and stable performance. High Quality: Made of PTFE and high quality magnetic steel, the magnetic stirring bar has fine workmanship, smooth surface, cylindrical design reduces friction, improves smooth rotation and stable stirring speed. Application: It is suitable for stirring liquids or solutions in school laboratories, biology, chemistry, scientific research, medical treatment, etc. It can also be used for stirring mixed substances. Specification: Item Type: Type C Stir Bar Material: PTFE Length  Diameter Quantity 10mm     4mm       1pcs 15mm     6mm       1pcs 20mm     6mm       1pcs 25mm     7mm       1pcs 30mm     7mm       2pcs 35mm     8mm       1pcs   Package List: 7 x Stir Bars Package List