Rechargeable Standard Battery, 500mAh, NiMH
From Amazon
Energizer E301375700 Pre-Charged NiMH Battery Rechargeable Universal AAA 1.2 V 500 MAH, Pack of 4 Silver
Conrad Electronic
Energizer Universal HR03 AAA battery (rechargeable) NiMH 500 mAh 1.2 V 4 pc(s)