Symmons Commercial Process Control Temptrol Stainless Steel Thermostatic Mix Valve 5-200-1B. I was using this valve to mix water for a reverse osmosis system.
It was working properly when the system was decommissioned, and I shelved the valve. It has 3/4 female NPT inlets and outlet and is rated up to 14 gpm, depending upon system pressure differential. And rebuild kits are available.
Save a bundle over new, and grab this one!