EDT Backwater Valve 160mm - Single Flap with stainless steel plate. Backwater valves (non-return valves) secure residential units on lower floors and basements against backflow of sewage into piping systems that result from blockage of main lines or flooding caused by rainwater. The use of backwater valves is mandatory to face these emergency conditions, according to international building standards. EDT backwater valves are equipped with an automatic closing system that starts to operate when flood-water appears and close in the event of inverse water flow. Single lockable backwater valve for waste water. The valve prevents backflow from the sewer and the lock function is ideal to “seal off” the sewer for maintenance. The flap is made of stainless steel preventing rodents from coming up the drain pipe. The removable flap assembly allows for maintenance and rodding if needed. ABS design will ensure hassle free use for years. This product should form part of any installation. Great value and functionality.