I have a new Sonoff button. As I was playing with it I attempted to remove the back. I have a 1.1 inch diameter disk that fits pretty tight in the slot. I cannot for the life of me rotate the back. I can partially pry up the back but don’t want to snap anything.
Anybody been able to do this?
Something big and flat to turn it…but still….that might even be blood! 
But as you can see, I have butchered it! It now opens and closes by hand though.
Edit: I have also taken the magnet out as it was too strong, pulling the battery out and causing loss of connection on the battery terminals. Other than all this, a good button LOL.
On the hard to open ones, I put some candle wax to help the next time.
I got mine open. I had to put the disk that went into the bottom slot into a vice and really turn the body.
The good news is I found how to make it easier to open and close. Two things:
This is the actual design solution, and yes, you need 3 hands – my wife presses a steel probe through that hole while I hold the case in one hand and use a coin to turn the slotted base. It is infuriating.
I see that now. The graphic could be clearer.
I would guess yours's is the newer design. Simpler magnet shape and no pawl needing the hole in the case and 3 hands to open.
I figured that I could use a piece of alien tape( clear thick “removable”) on the back and stick the button to my desk, then spin off the lid, usually works
The force (torque) I needed I doubt tape will do the trick unless you also use a paper clip in the hole.
That is unless you have one like @RobDaBush.
