From the IEC name one would suppose that this battery is a stack of 8 × LR50 or PX1 but I can find no further references at this time.
8LR50, 8NR50, 138, A138, E138, EN138A, EXP138, H-P8, HM-8P, PC138A, TR138, TR138R, V138PX,
not to scale.
Length × Diameter.
|Chemical Composition.||Nominal Voltage.|
|138.||No data available.||No longer in general production, small companies make an Alkaline replacement.||12 volts,|
(10.8 volts for original Mercury types).