Rubber Seating Rings: Primarily intended to "Cushion" insert bearings in pressed steel plummer / pillow block housings. Located between the bearing outer ring and housing bore, they dampen vibration and noise and enable the bearings to be displaced slightly in their housings to accommodate small shaft elongation or misalignments. For some applications, rubber seating rings may be fitted to the insert bearing outer rings to convert insert bearings to support rollers, and serve as tyres that will run quietly and protect the counter surfaces. The seating rings in the RIS 2 series are made from acrylonitrile-butadiene rubber (NBR) and have a convex spherical outside diameter. The rings can operate at temperatures from −30 to +100 Degrees Celsius. Benefits: Cushions vibration, allows misalignment, deals with small shaft elongation loads.