Power Pack For the longest possible duration, the Lithium Polymer is the battery of choice. Specifically designed for the Active 10, the chemistry in this battery is optimised for long duration over a wide range of temperatures & conditions. There is a wide range of power options available for use with the Active 10, allowing you to choose the one which suits your needs best. AA batteries give you the flexibility to carry spares & easily swap them half way round a walk, whereas the Lithium Polymer rechargeable option could end up being more effective when the unit is used on a regular basis. Whichever option you choose, it is always advisable to remember the power saving tips to get the most from your battery (see the User Guide). This Power Bundle comes complete with 1 x Li Pol 2, 700m Ah battery, specifically designed for the Active 10, which fits inside the standard AA back. Also supplied is a wall charger with multi region interchangeable heads (UK, USA, EUR, AU), a car charger, a spare USB (Universal Serial Bus) cable & instructions for use. For maximum flexibility the Active 10 with this Li Pol battery fitted, can thus be recharged via the USB (Universal Serial Bus) cable from Laptops, PC's, 110/240V wall sockets, & 12V cigarette lighter sockets.