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 6240-00-269-3346
NSN 5945-01-446-7074
NSN 5998-00-258-4498
NSN 5998-01-573-1162
NSN 6610-01-172-3707
NSN 5975-01-521-3275
NSN 5910-00-925-6962
NSN 4140-01-509-2490
NSN 7035-01-393-6015
NSN 6620-01-462-5196
NSN 5930-01-592-6147
NSN 5895-00-145-7780