The Lithium batteries can come as a single D cell (2901B) or as an increased capacity two-cell battery pack 2901B-P.
Rechargeable 12V Sealed lead acid batteries (6907) in different capacity ranges or 7.4V Lithium Ion battery packs (6911) are maintenance-free and play an integral part in ensuring reliable performance at unmanned data logging sites when recharged via a solar-powered recharge system.