Back UPS Pro BR 900VA 6 Outlet AVR LCD Interface (BR900MI) - Max Configurable Power (Watts): 540 Watts / 900VA, Input frequency: 50/60 Hz +/- 3 Hz Auto-sensing, Output Frequency (sync to mains): 50/60 Hz +/- 1 Hz Sync to mains, Transfer Time: 10 ms typical : 12 ms maximum, Interface Port(s): USB, Expected Battery Life: 3 - 5 years