This is a high-performance replacement vacuum battery for the IROBOT Roomba 4100, guaranteed to meet or exceed the OEM specifications of your original. The vacuum battery is 7.08 x 2.01 x 1.96 inches with an output of 14.4 volts. The chemistry is NIMH at 3500mAH capacity. Manufactured by Empire Scientific, model number VNH-100. 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.