Oxygen breather. A metal tube with ascrew attachment at one end, a white painted mouthpiece at the other. A clip is attached by a leather thong. On a label: 'Oxygen breather from German Submarine Deutschland (U155) Harwich ... 1918'.

‘Deutschland’ was a cargo U-boat operated by Germany during 1916-1917 to break the British blockade. When America came into the war it was converted to an armed U-boat and renamed U155. She was surrendered to Britain at the end of the war and was displayed in various ports before being broken up at Morecambe in 1922.