General EP-728 Hearing Aid "A" Battery The General EP-728 1½ volt "A" battery was used in 2-piece vacuum tube aids in the 1940s. It was often paired with an EP-901 22½ volt "B" battery which was of similar shape and size. This battery was manufactured by the General Dry Battery Co. It weighed 3¾ oz., and measured 3 7/8" in height by 1 1/8" in diameter. | | Click picture for larger view | | | | |