The rubber o rings are widely used in industrial applications. There can be o ring seals, o ring gaskets used for various purposes. The basic purpose of o rings is to seal mechanical parts against air or liquid or any fluid movement. It is a loop of elastomer with a round or o-shaped cross-section which can be used as a mechanical seal. O Rings are designed to be seated in a groove and compressed between two or more parts during assembly thereby creating a seal at the interface.