Relief Knob

The knob is used to relief the stress you might experience when you want to turn the know of the shower thermostat (temperature control).

You may suffer from arthritis - or perhaps the thermostat is just worn and difficult to turn - or maybe it'll help you children to better grasp the knob when it's wet?

In my case I removed the original (right) cover and pressed this knob onto.
I haven't tested it, but I may very well fit on the left side too?

If it dosen't fit yours then try to scale it up/down.

EDIT:
I experienced that the knob after some time started to come loose. So, I decided to make the inside hole a bit deeper (ShowerKnob_v.2.stl) - this secures it better as I slides further onto the thermostat.