My father likes to have a clock in our bathroom. Currently, it looks like this:

As you can see the clock is already damaged because we need to move it all the time when we want to open the window. I would like to mount it on the wall, but we have tiles there and cannot drill a hole there.
The clock has the usual "hole" to mount it on the wall with a nail:

I would like to have something like TESA powerstrips which holds very good, but with a knob on it so that we can easily put the clock on the wall and remove it if the battery runs out. How is something like that called?

I've had them stick solidly to windows for years.
– Wayfaring Stranger Dec 28 '14 at 00:38