High quality materials:The bearing is made of high-precision bearing steel, Even at high speeds or heavy loads, it can ensure high precision, durability, and wear resistance,The dual rubber seal provides excellent anti-corrosion protection.Save grease and prevent impurities from entering. widely applicable:Universal high hardness bearing steel double rubber sealed deep groove ball bearingSuitable for deep groove ball bearings on wheels of automobiles, bicycles, motorcycles, carts, mechanical applications, electric motors, skateboard wheels, lawn mowers,miter saw, air compressors, etc., if it produces noise, cracks, low speed, and friction differences during operation. Easy to install:Ball bearings provide stable performance through quenching processes, and by uniformly pressing these low friction bearings, they can prevent tilting or skewing of the bearings. Size packaging:Dimension: Inner diameter: 20mm, outer diameter: 52mm, thickness: 15mm. Packaging:(2 Pcs)6304-2RS deep groove ball bearing. Before purchasing, please carefully check the model to avoid confusion. It is best to touch the bearings with gloves to prevent them from rusting, as your fingers may sweat