A tin helmet, probably intended for use by air raid wardens.
Schoolteacher and union activist Natalia Davies founded the Defence Society in Adelaide in February 1933 by . By the commencement of World War II, the Society with Davies as President had a membership of 130, mainly women.
'From 1940 ... evening classes on first aid, home nursing, motor engineering, elementary electrical work and fire drill [were held]. ... the society taught hundreds of women to shoot and maintain a rifle. In 1942, after Japan entered the war, classes extended to pistol shooting, map-reading and unarmed defence. Each night members went on duty at a roof-watching post in the city'.[Australian Dictionary of Biography Online: Davies, Natalia (Nat) (1907 - 1951)]