What manufacturer and model number ?
You may have a pressure balance valve which is only to balance the flow between hot and cold water, for example if someone flushes the toilet while you’re showering. Most valves will not compensate for the pressure drop on the cold side and the shower head water would get hotter. There is also “scald guard” types of valves.
If you get me that info (make and model) I’ll get you the correct answer if it’s a quality valve. If I don’t know the answer right off I can bounce off one of the techs at my old plumbing company
I usually cruise FR a couple times a day
I think it has both. It has a springy, diaphragm-looking thing, AND a flow restrictor - at least, according to the instruction sheet (we haven’t taken it apart, yet.)
I’ll let everyone know when we install it.