Olympus BR-404 - battery 4 x AAA type NiMH

Having sufficient power for your audio device is always a crucial concern with voice recording. The BR404 rechargeable battery means you can forget about ever running out of power at the wrong moment again. Rechargeable and reliable, this battery is perhaps most notable for its incredibly low self-discharge: If you were to fully charge it and leave it for a year, it would still have retained 90% of this charged power.