Bought two of these, One cost £15 the other only £8.
The £8 one had manufacturing fault, which meant the front face place could not be screwed in firmly as the thread in the back plate was missing. (I used it while waiting for a new one, it failed in that time.)
The £15 one lasted 2 days and then failed.
Bought a Warmup thermostat for £96 fitted and working perfectly, wish I hadn't wasted money buying cheap rubbish.
Fitted in 15 minutes and works a dream. Total Tiles that sold it gave me good after sales service by replacing the control knob for free as I was a bit clumsy during installation.
This unit has a satisfying CLICK as the thermostat operates unlike other more expensive products, I like it!
I installed under floor heating in our downstairs wet room 15 years ago. The thermostat stopped working. The original was from Wickes and this is a direct replacement and is working well.