This is a high-performance replacement remote control battery for the Logitech M41B, guaranteed to meet or exceed the OEM specifications of your original. The remote control battery is 2.1 x 1.3 x 0.29 inches with an output of 3.7 volts. The chemistry is Li-Ion at 950mAH capacity. Manufactured by Empire Scientific, model number RLI-001-.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.