10 x Power One EVOLUTION size 312 hearing aid batteries 1.45V 6 blister PR41 brown. IEC Code: PR41. Manufacturer No p312. AZA 312, A 312, 312HPX, DA312, AC 312, 312DS, ZL3, A312, PR 312, 4607, 312AE, 312A, ZA 312, S312, ZA312, p312.