Easy cable management with these small fasteners, just put the cables inside and fasten it with (I used 3x32mm screws) and then slide on the cover upon the fastener, there is a little small trace the keeps the cover in place. Was a bit tricky to slide on the covers since I have contour wallpaper on the wall, but on a flat surface it shouldn't be any problem.
Cover is
48mm wide
14mm depth
183mm length