This is a high-performance replacement video battery for the Sony NP-FS31, guaranteed to meet or exceed the OEM specifications of your original. The video battery is 3.24 x 2.06 x 1.59 inches with an output of 3.6 volts. The chemistry is Li-Ion at 3000mAH capacity. Manufactured by Empire Scientific, model number BLI-173-2.3C. 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.