This is a high-performance replacement cordless battery for the Spectralink PBP0850, guaranteed to meet or exceed the OEM specifications of your original. The cordless battery is 2.44 x 1.5 x 0.548 inches with an output of 3.7 volts. The chemistry is LI-ION at 1800mAH capacity. Manufactured by Empire Scientific, model number CPL-537. 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.