The initial design of early leather flying helmets was adapted during the 1930s to become the iconic type B helmet which enabled the external attachment of radio earphones, oxygen masks, and removable goggles to protect pilots' eyes from the elements.[5][6]A detailed description of a typical Type B helmet can be found on the website of The Imperial War Museum (London, England). It is made from six vertical panels which meet at a central ridge panel running from front to back.