No - one end adjusts the temperature, the other is on/off.
The temperature has a preset 38C, and the knob has an indentation that clicks at that temperature position. The instructions give some guidance on ajusting the preset but it all looked too convoluted. 38C is a little too cool for me so I manually adjusted the knob just outside the indent. I end up doing this in most hotels I stay at too.
Works really well. Temperature seems consistent whatever the weather and I've not touched the temperature control once.
Flip. Mine was less than £50 including a stainless steel hose and basic shower head. I did however buy a fixing kit:
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I can't remember why - I think it made fitting easier. 15 quid though. Must have been necessary as most unlike me to splash out, as it were.