This is a high-performance replacement cellular battery for the T-Mobile MDA, guaranteed to meet or exceed the OEM specifications of your original. The cellular battery is 1.53 x 2.04 x 0.24 inches with an output of 3.7 volts. The chemistry is Li-Ion at 1200mAH capacity. Manufactured by Empire Scientific, model number BLI-969-1.2. 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.