The JCB 20951864 backup ring, also known as an anti-extrusion ring, is a critical component designed for JCB hydraulic cylinders. This genuine part prevents O-ring extrusion under high pressure, thereby maintaining optimal sealing integrity and extending the operational life of hydraulic systems. With precise dimensions including an outer diameter of 44.45 mm, an inner diameter of 31.75 mm, and a thickness of 2.38 mm, it ensures a secure fit and dependable performance in various JCB machinery applications.