This kind of bearing is used in automobile water pumps, textile machinery and aerospace, and is not used in other industries. There are many kinds of oil, mainly two categories, ordinary oil and grease. The gap between grease is too big, and the price can be several times different. If it is used for car water pumps, ordinary oil will do. The bearing consists of an inner ring and an outer ring, which are composed of rollers or steel balls and a retainer. The characteristic of the shaft bearing is that one bearing has no outer ring, and the other bearing has no inner ring, which act on each other’s raceways. It is equivalent to a cylinder liner, but has more raceways, steel balls or rollers and retainers than the cylinder liner. These two bearings work exactly the same and can replace each other. If the material is the same, the production process is the same, and the quality is the same, only the noise index, service life and speed are different.