SL04 series bearings are of sealed structure and filled with lubricating grease. The inner ring of the bearing is a coupling part with four ribs, which is integrated by a connecting ring. The outer ring has an integral middle flange, which serves as the rib of the rolling elements on both sides. There is a large distance between the two rows of rollers of the bearing, so this kind of bearing can also bear the appropriate tilting moment. Some products can be coated with special coating to be suitable for working conditions with severe corrosion. This series products are mostly used in hoisting and transportation machinery, such as rope pulley and pulley block.