With an extra 7.4V battery you can double the heating time.
This 2600mAh 7,4V battery with powerbank is suitable for the Nordic Heat Base Layer, Vests, green Jacket and Heat Seat.
The battery is charged with the same charger as included with all 7.4V Nordic Heat products.
Can be used with advantage throughout the year, as this also helps to motion the battery in the hot months, for example on a trip in the mountains, the forest or to the beach.
Please, remember to ALWAYS FULLY CHARGE the battery BEFORE STORAGE during the summer! (the safety print inside the battery use a little power every day, and will shut down the battery for ever when totally discharged)