This is a high-performance replacement cordless battery for the SENNHEISER 504374, guaranteed to meet or exceed the OEM specifications of your original. The cordless battery is 1.29 x 0.71 x 0.15 inches with an output of 3.7 volts. The chemistry is Li-POl at 200 mAh capacity. Manufactured by Empire Scientific. 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.