Samlex SEC-1223BBM 23 amp Switching Power Supply with Built-in Battery Back-up Circuit AC-DC Desktop 120 Volt Advanced Switch Mode Technology Reliable, 12V Nominal DC Uninterruptible Power Source(DC UPS) in conjunction with external 12V Lead Acid battery backup circuit High efficiency, compact and portable Protected against short circuit, overload, over voltage andover temperature Cooling by temperature controlled fan improves efficiencyand prolongs life of the fan