(n.) Well Completions. A supporting ring used with an O-ring, or similar seal, to prevent extrusion of the seal material under high differential pressures or excess wear under dynamic sealing conditions
Schlumberger Ltd. (The World's Leading Supplier Of Technology, Integrated Project Management And Information Solutions to Customers Working in The Oil and Gas Industry Worldwide), Schlumberger Oilfield Glossary Cedex, France 2014. http://www.glossary.oilfield.slb.com/en/Terms/sym/ a.aspx, (Ergo - Brit) {766}