The Shure SB901A is a rechargeable lithium-ion battery designed to be a direct replacement for batteries from Shure Microflex Wireless systems. It works with the MXW1, MXW6, and MXW8 transmitters. Replace your worn-out or missing battery with a fresh one, and give new life to your transmitter. The SB901A installs easily due to the integrated cable and battery connector.