IEC 61951-1:2017 specifies marking, designation, dimensions, tests and requirements for secondary sealed nickel-cadmium small prismatic, cylindrical and button cells and batteries, suitable for use in any orientation, for portable applications. This edition includes the following significant technical changes with respect to the previous edition: - addition of battery type; - revision of Figure 3 (6.1.3.1); - addition of “Optional pip” note to positive contact; - changed leader line position from pip to flats of positive contact (B and G).