Rubber O-rings are an extremely popular and widely used type of seal. O-rings are a doughnut shaped seal typically used to stop the passing of air or fluid in or out of a defined space. These products prevent leakage in critical high-pressure, vacuum, and hydraulic systems. Allstates Rubber & Tool Corp. supplies rubber O-Rings to many different industrial and commercial sectors such as: OEMLaboratoryPharmaceuticalEngineering