Piston rings are used for sealing cylinders. They can work at higher temperatures than elastomeric, fabric, or polymer seals. Two main types of piston rings are used in combustion engines: compression rings and oil control rings. Both types of piston rings are available from suppliers in North America and around the world. Compression rings and oil control rings that bear the CE Mark or meet specifications from the Society of Automotive Engineers (SAE) are also available.