I didn't have enough space to put my wifi relay module inside a surface outlet, so I designed a piece to put it on the back. 

There is no fastening system, the piece is sandwiched between the socket and the mounting surface.

The module is held in place by double-sided tape.

Single socket Outlet

The spacer is made for the Schneider Electric Mureva Styl

Print specifications :

• Add supports under the centering pins :

Double Socket Outlet        

It's adapted to an old noname socket, i attach the .stp for modifications needs.

05/05/23 :  Added V2 of the double socket outlet spacer (+2 mm depth, suitable for Sonoff mini module )

08/05/23 : Added V1 of the single socket outlet spacer