My thanks go to Z. Sun. for passing details of this battery on, complete with reference links, making this page possible.
Two of these cells made up the 2R10 (Duplex) battery.
#4, 927, BF, R10, R10S, U8,
not to scale.
Length × Diameter.
|Chemical Composition.||Nominal Voltage.|
|R10.||37 mm × 21 mm|