Our  AC to DC 3.5mm External Power Cable provides all of the KR-S80 series locks with external dc power via an AC adapter.  It can be plugged directly into the lock for full power with out the use of batteries or it can be used to power up to 5 locks that are chained together.  The cable is a USB to 3.5 mm cable at 19.5 inch that plugs into the 115 VAC adapter.