MK.IV bayonet connector. Stores ref. 6D/526. Brass plated fittings normally found at the lower end of the standard wartime issue corrugated rubber oxygen tube. These were normally used with cadmium plated 'crocodile' clothing clips attached - see photo no.7 for one shown in use. Good used condition. Some tarnishing and minor corrosion in places. Most are Air Ministry King's crown marked, one is War Department broad arrow marked. Stock code O5222.