The seal ring M20X26, code 100100, is a precision sealing component used in the MAN L21/31 engine to establish a reliable barrier at a connection where its specified M20X26 dimensions are required. Depending on the particular installation point, the seal ring may prevent leakage of lubricating oil, fuel, cooling water, compressed air, or another operating medium while also helping protect the surrounding system against contamination. During engine operation, the ring can be exposed to pressure variations, vibration, temperature changes, mechanical compression, and continuous contact with the relevant operating fluid, making dimensional accuracy and suitable material properties particularly important. Correct installation and appropriate tightening of the associated connection ensure that the ring is compressed as intended without being damaged or excessively deformed. By maintaining a dependable seal, the M20X26 seal ring helps prevent fluid losses, protects adjacent components, reduces maintenance requirements, and contributes to the safe and reliable operation of the MAN L21/31 engine.