This battery holder can hold 6 AA battery which can make 7.2 V rechargeable battery pack from NiMH / NiCd cells or 9V battery pack from alkaline cells.
It comes with a DC2.1 Powerjack which can plug to Arduino directly.
Specifications:
Battery Quantity: 6
Battery type: AA
Storage temperature: 25°C (77F, Room temperature)
Max Operate temperature: 80°C (176F)