The Fishman PRO-BPK-101 Rechargeable Battery Pack is a universal power solution that requires no modifications to your guitar. It can be used to power Fishman Fluence pickups and other 9-volt accessories. The built-in LED indicators let you know when the battery pack is full and when it needs charging. You can fully recharge this battery pack in only 3 hours using the included mini-USB cable. Once fully charged you can rely on this battery pack for up to 200 hours of playing time.