uninterruptible power to any critical load by automatically or manually selecting between one of two AC input sources. If the preferred source deviates outside preset limits, the unit will instantaneously transfer to the secondary source. Upon return of the preferred source to within acceptable limits, the static switch will automatically transfer the load back. This insures that the sensitive load is always being supplied the best available power from two sources. Switch sizing ranges from 20A thru 100A and each can be configured with single or double poles.