Product details:

The WaterBlock is an excess flow safety shut-off valve which controls the maximum continuous flow of water. Its function is to measure the number of gallons of water that passes through it. If this quantity exceeds the set value, the WaterBlock stops the flow and keeps this safety condition until user intervention. If the water volume does not exceed the set value, the WaterBlock mechanically and automatically resets to the measured volume set point. The WaterBlock is now ready to restart a new measurement cycle. The WaterBlock does not require power; simply water flowing through it is all thats needed. The WaterBlock is suitable for both hot (158 F) and cold water. Model WB-13R has a volume capacity of 13 Gal.