Apc BK500EI Back-ups Cs 500va 300wattsusbhot Swap Battery, Input frequency 47 - 63 Hz, 50/60 Hz +/- 3 Hz Auto-sensing, Power Cord-2, Lead-acid battery, Battery Charge Power (Watts) 10 Watts, Interface Port(s) Optional Simple Signalling RS232 cable, USB, Beige. Apc protect secondary electronics from surges and spikes without reducing battery power used to run primary electronics during an outage. Reserves power capacity and run time for connected equipment that require UPS battery back-up while providing.