We have two showers, one in the bath for the bathroom and one in the walk in shower for the ensuite. The Hans Groehe mixer units drop into their “I box” whichis sunk in the wall. A good feature is the button on the fatter lower knob which controls the temperature. This has a middle default “upper limit” position to avoid scalding yourself or children.
The upper knob is the on/off control and diverter where required for the bath/shower, or just the on off control in the case of the shower.