A rigid item usually circular in shape, designed to accommodate a bearing. It positions the bearing but does not encase it or restrain its motion.
rubber butadiene-acrylonitrile class nbr retainer material, 0.3650 inches minimum and 0.3850 inches maximum overall width, 1.2500 inches nominal bore diameter, 2.0020 inches minimum and 2.0060 inches maximum outside diameter, c-17a,aircraft end item identification