Dont like the idea of rechargeable battery instead of std 9 volt. Those normally last several months in active basses. Id rather have either 3band with selectable mids and treble freq's, or just 2band like mine has with selectable treble freq's. But for some the mid orientation of the east will be good choice. But main thing is I dont like reachrageable battery use. Cause in my experience they dont hold charge for as long as regular when expected to last long time like several months. Amd 9 volt durecells are cheap enough to be no problem getting new ones every 4-6 months or bit longer.