These parts are Side Plates, which are fixed by snaping in, into the aluminium profiles.
One Version is closed, with an eyelet on the bachside to fix cables.
The sevond Version has a rectangular recess (13,5 x 20mm) in the middle to mount for example the mainswitch.
The Third version has a recess, which fits to an IEC Socket.
The fourth version has an IEC and usb Socket
later I will create more versions