This is a high-performance replacement cellular battery for the Kyocera KX21 SWITCHBACK, guaranteed to meet or exceed the OEM specifications of your original. The cellular battery is 1.42 x 2.11 x 0.25 inches with an output of 3.7 volts. The chemistry is Li-Ion at 900mAH capacity. Manufactured by Empire Scientific, model number BLI-1052-.9. 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.