This Technical Report applies to primary batteries known as "button cells" and "small batteries" and used as the energy source of watches. Applications of such batteries in general are covered within IEC/TC 35, e.g. in IEC 86. However, specific requirements for applications in watches are not sufficiently covered by IEC 86. Therefore, ISO/TC 114 laid down this Report taking care of the justified wish of both manufacturers of watches and consumers to provide more detailed specifications and requirements for main dimensions of watch batteries, design, tolerances, nomenclature, and performance tests.