Quad seal (also called X seal) for M35A3 CTIS hubs. Two are used in each hub. p/n RCSK16048-2 or 12448547. NSN 5330014491978.
Note: symptoms that a seal needs replacing are air escaping from axle vents or a CTIS system that is very slow to build tire pressure, or audible air hissing out at a hub. If the tire fails to remain pumped up this seal is not the problem.