Ever Ready Blue R20B

The Blue R20B was a 1.5 V battery manufactured by the Ever Ready Company in Britain. It was approximately 6 cm in height and 3.4 cm in diameter. It was very slightly larger than the modern "D" size dry cell, which can fit in many applications, where the "Blue" was used. This battery came out of an avometer, which can also accommodate a "D" size battery because of the flexible metal spring clips.