1.Size:4 mm x 8 mm (Diameter * length) ; 2.Shape:Cylinder with Pivot Ring Shape ; Quantity: 10pcs 3.High-quality, Strong Magnetic, New & Clean & Cute 4.High temperature: the use of operating temperature up to 250 ℃ 5.Corrosion resistance: for most chemicals and solvents, showing inert, strong acid and alkali resistance, water and a variety of organic solvents 6.High lubrication: the lowest coefficient of friction in solid materials 7. Low temperature resistance: good mechanical toughness, even if the temperature dropped to -196 ℃, can also maintain a 5% elongation 8.No adhesion: with the smallest surface tension in the solid material, no adhesion to any substance 9.Weather resistance: long-term exposure to the atmosphere, the surface and performance remain unchanged 12.Non-toxic: with physiological inertia, as artificial blood vessels and organs long-term implanted in vivo no adverse reactions