The Shure SB900B Rechargeable Lithium-Ion Battery Pack is a high-quality, reliable power source designed specifically for Shure microphone receivers. With its wireless connectivity and dynamic transducer type, it is perfect for live performances where musicians require freedom of movement while performing. The sleek black color and compact form factor make it easily transportable and unobtrusive during performances. This battery pack ensures that your Shure microphone system stays powered up and ready to go whenever you need it.