It has a wider mouth to allow easy insertion, but after inserting it a bit further it's quite tight (doh, from now on inserting this plug will not be the same).I've found the tolerances to be perfect in the STL file. It's easy to insert or remove the plug, even without a precise aim. However, it's a parametric SCAD model so you can adjust it to your needs with OpenSCAD.If the wall's surface is uneven, I recommend mounting it with spacers (e.g. an M6 nut) between the plate and the wall. This is to avoid deforming the back plate. Use the washers to avoid deforming the mounting plate's holes.Print it with a high infill (e.g. > 35%) so that it will be quite strong and last many years.It will fit plugs such as Mennekes plugs that are made according to VDE-AR-E 2623-2-2. Note: The version 1 holster that is meant for the Male Type 2 plug has not been tested yet.