1、With polished smooth surface, it works well with high efficiency causing low noise. 2、High temperature resistance, able to operate at a temperature range of -20-200℃ or so. 3、Adopting premium bearing steel material, solid enough for a long term use. 4、Wide applications in many fields: industrial machines, cars, ships, household appliances, health care system, etc. 5、2 Rubber seals protect it against water and dust or any other objects invasion. Features: With polished smooth surface, it works well with high efficiency causing low noise. High temperature resistance, able to operate at a temperature range of -20-200℃ or so. Adopting premium bearing steel material, solid enough for a long term use. Wide applications in many fields: industrial machines, cars, ships, household appliances, health care system, etc. 2 Rubber seals protect it against water and dust or any other objects invasion. With 10 pcs in package, you can keep them for spare, very practical in our daily life. Specification: Material: Bearing Steel Type: 6001-2RS Color:Silver(Shown as pictures) Inner Dia: Approx. 12mm/ 0.47inch Outer Dia: Approx. 28mm/ 1.10inch Thickness: Approx. 8mm/ 0.31inch Application Temperature: -20-200℃ Quantity: 10 Pcs Weight: Approx. 195g Packing List: 1 x 10 Pcs Ball Bearings