Use w/a valve cap
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 5895-01-106-4161
NSN 5930-01-060-4899
NSN 5945-01-133-5550
NSN 6320-01-652-3806
NSN 5915-01-341-5695
NSN 5965-01-627-2606
NSN 5945-01-211-6585
NSN 6610-01-483-1317
NSN 6685-00-326-0724
NSN 5920-01-389-9582
NSN 6320-01-420-0340
NSN 5920-01-006-9821