Tascam BP-6AA External Battery Pack BP-6AA
The BP-6AA is an external battery pack for TASCAM handheld recorders. It mounts to the bottom of your handheld recorder using a tripod screw and powers the handheld recorder through the USB cable. Since the BP-6AA itself also has a tripod connector, it can be mounted to a desktop stand.
The BP-6AA battery pack increases DR-40's already-impressive 17.5 hour battery life to over 50 hours of recording.