A Second World War British Slidex cipher device marked 'Camp Staff Clancy'. The cipher device, a paper-based manual cipher system, includes two OPS/SIGS cards. It also has two sets of rulers — black (for divisional headquarters) and green (for battalion and other units). The Slidex is supposed to have three sets of rulers, the third being red (for army headquarters). The device folds in two, with the right side being the cipher device itself and the left half being a pocket for storage of spare cards, rulers and an operating instructions booklet. The booklet is not present in this example.