Cryogenic oxygen ground coupling used to fill the Apollo CSM's oxygen tanks pre-launch, measuring 10″ long with a diameter of 3″, marked on the side: "Coupling, Ground, Fill, Oxy, NAA/S & ID Control No. ME278-8020-0001…Contract No. NAS9-150." This coupler would mate with a corresponding Service Module side coupler during pre-flight operation, with disconnect occurring upon retraction of the launch pad swing arms shortly before lift off. A worn material condition tag is attached, noting a "leak around inner seal." In fine condition.