APC Back-Ups 500VA with AVR (BX500CI) - UPS type: Line interactive, rated power in W: 300 W, rated power in VA: 500 VA, Main Input Voltage: 230 V, Main Output Voltage: 230 V, network frequency: 45...65 Hz, output frequency: 50 Hz sync to mains, 50 Hz +/- 0.1 % for 50 Hz nominal unsynchronized, Transfer time: 6 ms typical : 10 ms maximum, battery voltage: 12 V, Surge energy rate: 273 J, control panel: LED status display with on line : on battery : replace battery and overload indicators, number of cables: x 1, mounting support: Desktop, mounting mode: Not rack-mountable