Original model description: Replacement mounting plate. Indices on the inside for easy orientation. Small grooves in the mounting slit which prevent spontaneous dislodgement whilst still allowing for tool free attach- and detachment.
Remix: added ~5mm more space between the AP and the mounting surface.
The author remixed this model.
Added extra ~5mm thickness to add some more space in case this is mounted on a not-so-ideal surface.