If you want to mount multiple covers on a box, you can use extenders. Melt M3 brass inserts into the holes of the Extender on the locations of the Covers you want to use. Leave the corners open en use a longer screw to fix the covers and extender to a box. The bottom of the Extender has an indent on the edge, just like the covers, so check this before melting the brass inserts in.
Extender1x1
An Extender with an outer dimension of 39,8 mm x 39,8 mm is 10 mm high.
Download the STL file: Extender 1×1.stl
Extender 2×1
An Extender with an outer dimension of 79,8 mm x 39,8 mm is 10 mm high.
Download the STL file: Extender 2×1.stl
Extender 2×2
An Extender with an outer dimension of 79,8 mm x 79,8 mm is 10 mm high.
Download the STL file: Extender 2×2.stl
Extender 3×1
An Extender with an outer dimension of 119,8 mm x 39,8 mm is 10 mm high.
Download the STL file: Extender 3×1.stl
Extender3x2
An Extender with an outer dimension of 119,8 mm x 79,8 mm is 10 mm high.
Download the STL file: Extender 3×2.stl
Extender3x3
An Extender with an outer dimensions of 79,8 mm x 79,8 mm is 10 mm high.
Download the STL file: Extender 3×3.stl
Extender 4×1
An Extender with an outer dimension of 159,8 mm x 39,8 mm is 10 mm high.
Download the STL file: Extender 4×1.stl
Extender 4×2
An Extender with an outer dimension of 159,8 mm x 79,8 mm is 10 mm high.
Download the STL file: Extender 4×2.stl
Extender 4×3
An Extender with an outer dimension of 159,8 mm x 119,8 mm is 10 mm high.
Download the STL file: Extender 4×3.stl
Extender 4×4
An Extender with an outer dimension of 159,8 mm x 159,8 mm is 10 mm high.
Download the STL file: Extender 4×4.stl