In 1937, The British specified a web pattern, for use in personal equipment, made of woven waterproofed cotton, and used it though out the war. The main body of the case is comprised of a yellowed piece of celluloid reinforced along its edge with webbing, which expands, accordion-like, from the back of the case. Inserted into the opened top is a stiff brown which serves as the shape-retaining backing. Nice clean case.