Evolution Aqua Double Union Ball Valve 4"Part of the Evolution Aqua range, this Double Union Ball Valve is designed to provide a reliable and easy to use solution for controlling water flow within ponds, filtration systems, aquariums, and a wide range of water installations. Designed for 4" pipework, this ball valve is ideal for helping control, isolate, and regulate water flow within pond and filtration systems where reliable shut off and maintenance access are important. The double union