Reference parts book 0532-lp-103-0916, section 6, page 91, figure 6.43, item 1
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 6145-01-208-3678
NSN 6130-01-052-2937
NSN 5945-01-062-0800
NSN 6105-01-543-5539
NSN 5950-01-325-7805
NSN 5835-01-342-2654
NSN 5930-00-455-0163
NSN 5920-00-285-2245
NSN 5996-00-164-7288
NSN 5915-01-013-8995
NSN 6145-01-499-9745
NSN 6135-01-275-1363