Stores Ref. 6D/560. Comprises a length of unbraided black rubber oxygen tube with a MK.3B* (6D/101) bayonet connector at one end and a MK.4A 'socket' connector (6D/482) at the other. These enabled the use of E-series, G-type and H-type masks in older aircraft fitted with early oxygen systems. These adaptors were also used to connect masks to portable (walkaround) oxygen bottles. The tube is in excellent flexible condition with no evident cracking or deterioration. Both brass connectors are in very good condition and correctly attached with twine bindings. Stock code O21067.