2021 upgraded version with smooth polished surface, smooth operation, high efficiency and low noise. High temperature resistance, can work in the temperature range of about -20-200 ℃. Made of high-quality bearing steel, it is strong enough for long-term use. Widely used in many fields: industrial machinery, automobiles, ships, household appliances, health systems, etc. 2 rubber seals prevent water and dust or other objects from entering. Features: The surface is polished and smooth, with high working efficiency and low noise. High temperature resistance, can work in the temperature range of about -20-200 ℃. Made of high-quality bearing steel, it is strong enough for long-term use. Widely used in many fields: industrial machinery, automobiles, ships, household appliances, health systems, etc. Specification: Material: Bearing steel Model: 6001-2RS Color: Silver (as shown in the picture) Inner diameter: Approx. 12mm/0.47in Outer diameter: Approx. 28mm/1.10in Thickness: Approx. 8mm/0.31in Working temperature: -20-200°C Quantity: 10pcs Weight: Approx. 300 grams