These seals are readily available in Imperial sizes from 1/8 inch to 3 inches. French and German Metric sizes form part of our extensive stock. Bonded Seals were originally designed to replace copper-type washers that are used in high-pressure systems. They comprise of a metal washer and an elastomeric ring which is bonded inside the diameter. The metal washer prevents over-compression and limits deformation of the elastomeric ring.