This lets you use JeeNodes with batteries. Either the 3- or 4-cell unit is fine, the 4-cell provides higher voltage/more mAh capacity. Depending on whether – and how well – sleep mode is implemented in the code running on the JeeNode, the batteries can last from a day to over a year.
A slide switch is incorporated in the housing. For more permanent, long-term installations, the switch is not needed (and is a possible point of failure if high humidity affects the internal contacts). Use the No Switch option.
The standard battery holder is for 3x AA, either alkaline or NiMH (the one pictured here was for smaller AAA-sized batteries). You need to supply your choice of batteries.
There is also a 4x AA version if you need a higher voltage/runtime, i.e. 5V or more with NiMH (rechargeable) or up to 6V with Alkaline. You need to supply your choice of batteries.