This junction box is supposed to cover even larger holes in the ceiling to avoid filling and painting the ceiling. Whereas typical junction boxes have a diameter of about 70mm, this box has an outer diameter of 110mm to cover a larger area.

It has a large hole in the center of the box to feed through a cable from the ceiling. The box can be screwed in place with two screw holes. The cable can be fed out of a hole in the side. The cap can be screwed on after mounting the box to the ceiling.