Extended Stand-offs 50 mm for M4 screw

You need just one hook to hang a ceiling light and at least three of theese stand-off sets for leveling. I use a cable tie to hang a lamp in one point (between the lamp and one already installed ceiling hook), than I tie the cable tie. At the end by expanding stand-offs I adjust horizontal, parallel leveling with the ceiling surface. No additional drilling is needed. 

I print them with brim for better print stability. 

Inner diameter of the threaded tap part is M4.