BWSP, Combo Sump Pump System, Primary & Back Up Sump Pump System, Pre-Assembled, Ready For Easy Installation, Includes 1/2 HP, 2.820 GPH At 10', A/C Sump Pump & Watchdog Special Back Up Sump Pump, 1730 GPH At 10', Dual Redundant Floats On Each Switch, Battery Not Included, 1 Float Fail To Activate The Pump, The Second Float Takes Over, Operates As Long As It Is Receiving AC Power, If Power Is Interrupted, Or More Water Is Coming Into The Sump Than The AC Pump Can Handle, The Back Up Sump Pump Will Begin Pumping Automatically, Features Diagnose A Problem & Sound An Alarm, A Light On The Display Panel Of The Control Unit Will Indicate The Cause Of The Alarm & The Corrective Action.