Mopping up after flooding is made easy with the model R400D. The Mop-up® features a unique non-return valve built in below the impeller. The rubber clad bottom helps protect against damage to floor surfaces. Pumping down to 1/12 of an inch and starts up in only a small puddle of liquid, and features a special diaphragm valve that prevents water backflow. Perfect for easy clean up of floods, and spills in basements, businesses, industrial and recreation areas.