Blue anodized metal valve knob produced by Air-Lock for the Apollo space suit, measuring approximately 1 x 1.25 x 1.5, engraved with part numbers on the base, "PN-1926, SN-429," and hand-etched on the knob, "Class III." In fine condition. This knob has been authenticated by Bill Ayrey, company historian at ILC Dover, the manufacturer of the Apollo, Shuttle, and Space Station suits, and is accompanied by a letter of authenticity. The knob would be found on the chest area of the Apollo astronaut's suit and was used to adjust the flow of oxygen: when attached to the Command or Lunar Module oxygen supplies, the suit received a gas flow 12 cubic feet per minute and the valve would be rotated so that the flow was split between the helmet and extremities; when connected to the PLSS during EVAs, the valve was adjusted to administer 100% of the gas flow to the helmet since the PLSS provided a maximum flow of 6 cubic feet per minute.
Terms and abbreviations used in our descriptions.