Each book contains 20 leaves measuring 2,5×0,5'' (Cobaltous chloride).

These test papers can be used for the quick and easy detection of moisture. Cobalt chloride paper is pink when moist and blue when dried at 40 °C – 50 °C. They can also be used to indicate when desiccants such as silica gel are exhausted. Other uses are to detect the detection of moisture in crates during transportation where the presence of moisture could induce deterioration by rust.