Thermostatic valve and rough-in valve - What is the difference of a rough-in valve and a thermostatic valve?

Two-Handle Thermostatic valve (aka thermostatic control) – has two handles. One controlling volume, one for the water temperature. Thermostatic valves contain an element that reacts to the temperature, not the pressure. You will see two handles on one plate.

One-Handle Thermostatic valve (aka thermostatic control) – has one handle for temperature only. Typically, you would purchase a volume control separately for this. So, you will see two handles and separate plates.