PowerWalker VFD APFC series is a standby/offline UPS for home and office applications and it is equipped with a technique that allows using the full power of UPS, even when used with APFC power supply load. Usually it is required to oversize a UPS to ensure secure backup when connecting a power supply with active power factor correction. With the implemented technology this is no longer needed. Therefore you can choose smaller cost-effective UPS (e.g. PowerWalker VFD APFC instead of usual offline or line interactive 1000 VA model).