Per research cage 63600 is the oem
A nonmetallic circular item with an aperature, having a solid round cross-section. They are used primarily for sealing. For items with other than round cross section, see packing,preformed. For noncircular items with a round cross-section, see seal,nonmetallic round section and rubber,round section.
NSN 5925-01-127-1864
NSN 5910-00-227-0848
NSN 6135-00-681-2702
NSN 5835-01-381-2683
NSN 6620-01-350-5103
NSN 5910-00-923-0531
NSN 5895-01-572-2657
NSN 6105-01-410-6725
NSN 5855-00-004-0904
NSN 6650-01-247-2002
NSN 5915-01-143-0937
NSN 5835-01-371-6482