This is a high-performance replacement video battery for the Sony NPFS31, guaranteed to meet or exceed the OEM specifications of your original. The video battery is 2.06 x 1.19 x 1.02 inches with an output of 3.6 volts. The chemistry is Li-Ion at 1300mAH capacity. Manufactured by Empire Scientific, model number BLI-173C. We offer a 1 Year Warranty with purchase. See this product elsewhere at a lower price? Call or email us; we have a Price Match Guarantee.