1941 A.D. or later.prising: a type C leather open face helmet wired for type Bmunication, oxygen mask with hose and alloy-framed flying goggles with padded leather and rubber band, the frames stamped 'Stadium Made in England Patent Reg Design'; the helmet with webbing chin strap, buckles and stud fasteners, chamois leather lining bearing ink stamp and handwritten 'Adams Progressive' 'No.75-78', plug holder with paper label, tubular oxygen mask inlet marked 'MLD 18' 'MC253D', microphone plug and hose with brass connector stamped 'D/156'; together with an RAF flight map and an RAF 'ditching' whistle of classic snail type with Air Ministry's crown markings and reference numbers '23/230' and '293/14/L1795'; the helmet mounted on a wooden 'mannequin' head. 6.1 kg, 31 cm (12 1/4 in.). Acquired from J C Militaria and Historic Flying Clothingpany. The Kusmirek Collection, UK.Apanied by copies of listings for each item. This type of helmet and system was introduced in 1941 A.D. [3]