D-Li122 Battery for Pentax Optio VS20 (1000mAh, 3.6V - 3.7V) Lithium-Ion battery Cellonic (Electronics)
Fuji makes very good cameras, alas room for the battery is low and you must carry around a bandolier full of batteries. The Cellonic batteries do what they can, abilities displayed by all manufacturers are often far from the truth and for good reason