"This is our best selling water mixing valve". Solid Brass, adjustable water mixing valve. Installed below sink. Including (2) check valves/back flow preventers. This valve is made of chrome plated solid brass. Has built-in ceramic disc cartridge. Inlets are 1/2 NPT male, outlet is 1/2 NPT female. The outlet is union style nut for added installation convenience. It has (2) built-in back flow preventers which eliminates commingling of hot and cold water in the water supply system. The knob enables installer or user to adjust water mixture that is delivered by faucet.