Prevent basement flooding with General Pipe Cleaners Flood-Guard®. Available for two-, three- and four-inch (50.8, 76.2 and 101.6 mm) floor drains, it operates like a check valve to seal off water backup caused by overloaded sewers. Water flows normally through the drain until the sewer begins to back up, then the float rises to seal off the drain opening until the water recedes. After quick and easy installation with a screwdriver, it can prevent property damage and messy clean-ups. Also available in a standpipe model for handling extreme extended pressure.www.drainbrain.com(800) 245-6200