A mount for an Ikea Tradfri button. 

It slides over an existing light switch and allows for magnetic mounting of the button. It has a little lip at the back that slides behind the plastic of the light switch to ensure a good fit.

The magnet is slightly off-center to accomodate for the off-center built in magnet.

Print in 0.2mm to ensure that little lip is just a single layer

Magnet can be inserted at the end as I left the back open. magnet dimensions: 10mm diameter, 2mm height. It's a snug fit that needs some persuasion to get it in.

The height is 4mm which is a perfect match for a little notch on the light switch cover