APS units automatically sense and switch to AC output between outside power and battery power when no AC power is available. Ideal for use as mobile power systems or stationary UPS/emergency power supplies. Models include an advanced 3-stage battery charger for quicker recharge, plus protection against over-charge and over-discharge to ensure a longer service life from batteries. High efficiency output is frequency controlled to support delicate loads. (USA) Watts: 2000; Outlets: Hardwire.