Rechargeable Standard Battery, 5000mAh, NiMH 1.2V
From Amazon
ANSMANN D Size Batteries [Pack of 2] Long Lasting Low Self Discharge Rechargeable D Type 5000 mAh NiMH MaxE Pro Battery For Digital Cameras, Flashguns, Toys, Audio Devices and Radio Controls
Conrad Electronic
Ansmann maxE HR20 D battery (rechargeable) NiMH 5000 mAh 1.2 V 2 pc(s)