The Delta Auto Drain is an optional add-on to the 5GE-SMP Series Steam Generator that automatically purges water from the system after each steam shower. Automatically purges the system by gravity once water in the generator cools Connects to a factory installed auto drain terminal block located inside the generator cabinet Valve body with 1/2" NPT brass female connection Designed for use with 208V and 240V 5GE-SMP Series Steam Generators (voltage should match the voltage of your generator) Inlet & Outlet Connection : 1/2" NPT Brass Female Thread