Mask tube assembly, Mk.I. Scarce oxygen tube specially designed for use with an emergency bail-out supply. Essentially the same as a standard tube with an additional smaller bayonet fitting at 90 degrees for the oxygen supply. The main Mk.IV bayonet fitting and clothing clip is fitted at the end as usual. The tube has minor cracking within the folds of the rubber but is still very sound and flexible. Good '+' condition and rare to find. Stock code O23406.