RAF Oxygen Mask Extension Tube

Standard wartime pattern corrugated rubber oxygen tube complete with Air Ministry marked brass MK.IV bayonet connector (6D/526) and white metal MK.IVB bayonet socket (6D/1300) at the bottom. The rubber tube is in good condition although it does have cracking within the folds when flexed. These  were used to extend the length/range of the standard oxygen tube. The connectors are 'thread bound' suggesting late WW2 or early postwar manufacture. Quite a rare tube to find. Stock code O14648.