Details: 

• 2 Packs of 10pcs, double-rubber sealed deep groove. prevent impurities from entering.
• Made of bearing steel for durability and resistance to rust, corrosion and deformity under heavy loads, and is Shields on both sides keeping lubricant in and contaminants out.
• It has a revolutions per minute (RPM) limit of 30,000 with grease lubrication.
• Rolling bearings use rolling elements to maintain the separation between moving parts to reduce rotational friction and support radial and axial loads.