An adapter for the IKEA Vitval bunk-bed to mount an Aqara Mini Zigbee One Button to the rear corner posts.
I'm using this button to control my sons night light.
The exact model number I ordered from Aqara on Aliexpress was the WXKG11LM which measures 45x45mm x 13mm deep with 9mm radius corners. Incidently this shows up as a "Lumi b1acn01" in home assistant.
Hopefully someone else may find this useful.