WAYNE 57729-WYNP WAPC250 1/4 HP Automatic ON/OFF Water Removal Pool Cover Pump iSwitch technology turns pump on and off by sensing the presence of water Plug in and leave the pump unattended for worry-free water removal Strainer base filters debris to minimize clogging and keep pump from tipping over Energy efficient, high flow, oil-free pump Automatic freeze protection within the iSwitch technology to prevent pump damage Auto On activates when water at, or above 2 1/8 in. has been detected. Auto Off activates when water at, or below 3/4 in. has been detected.