A threaded rod (4) with screw head is screwed into a wall plug. The screw head (2) is formed by a base plate (6) having an axial tube (8) with a threaded bore passing through the tube so that the threaded rod (4) can be screwed and fixed in the bore from the pipe side. The base plate can have reinforcement ribs (10) running radially from the pipe to the plate edge and tapering conically outwards. The threaded rod can be welded to the base plate. An adjustable washer (14) can be screwed onto the rod.
