Sump pump and backup sump pump system includes a basement Watchdog 1/2 HP (horse power) AC (alternating current) pump and a Basement Watchdog special battery backup system already assembled for easy installation. Compact footprint fits in sump pit as small as 12" in diameter. Back-up starts immediately after loss of power or if flow of water is too great for the AC pump alone. Dual float switches provide dependable activation for each pump. Unique monitoring controller sounds an alarm if maintenance is needed. Battery and acid sold separately. AC 3200 GPH (gallons per hour) at 10'. Backup 1730 GPH at 10'. 18" H x 11" W x 8.75" L. 2 year warranty.