AS Back-up Ring ID 2.77 - W 2.18

● Back-up ring introduction：also known as Anti-extrusion ring, which can improve the pressure resistance of O-ring or X-ring, prevent scars or twisting due to pressure, and effectively prolong life.
● Back-up ring specifications：8-1XX series.
● Back-up ring material：NBR90Black、FKM90Black。