This is a high-performance replacement cellular battery for the Huawei M660, guaranteed to meet or exceed the OEM specifications of your original. The cellular battery is 2.03 x 1.99 x 0.214 inches with an output of 3.7 volts. The chemistry is LI-ION at 1250mAH capacity. Manufactured by Empire Scientific, model number BLI-1291-1.2. 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.