Our UC 200 Series Insert Bearings are made from 52100 series bearing steel. The UC insert has a spherical OD which allows it to self-align while in various types of mounted bearing housings. It features a Neoprene Contact Seal designed to keep lubricant in while keeping contaminants out. The seal is designed to purge as new grease is gradually pumped into the bearing cavity. The seal is protected by a steel flinger positioned directly in front of the seal contact area. This flinger creates a barrier channel that makes it difficult for dirt and contaminants to get inside the insert bearing. When in operation dirt and debris are slung away from the bearing by centrifugal force. The UC insert comes standard as a regreaseable type with a grease access channel machined in the outside diameter. The UC Normal Duty Wide Inner Ring Set Screw Insert Bearing is factory lubricated with Chevron SRI#2 AW (anti-wear) grease. The insert contains 30-40% grease fill by volume. The UC insert comes standard as a regreaseable type with a grease access channel machined in the outside diameter.