Rechargeable Standard Battery, 550mAh, NiMH 1.2V
From Amazon
Ansmann AAA Size Batteries [Pack of 4] Long Lasting Low Self Discharge Rechargeable AAA Type 550mAh NiMH MaxE Pro Battery For Cordless Phone Handsets, Toys, Digital Cameras & Remote Controls
Conrad Electronic
Ansmann maxE HR03 AAA battery (rechargeable) NiMH 550 mAh 1.2 V 4 pc(s)