This Lithium Ion Battery from Mackie is intended for use with FreePlay personal PA systems. It is designed to provide up to 10 hours of continuous performance. At any time, you can check the battery level on your FreePlay personal PA by pressing the Channel 2 and BT/Aux buttons simultaneously; in doing so, the Running Man logo on the front of the PA system will illuminate to indicate battery life. The battery itself operates at a capacity of 5200mAh and carries a nominal voltage 7.4 VDC. Using it will allow you to replace the need to utilize eight D batteries in portable situations.