This holder is to IKEA's LED lighting to kitchen cabinets, I made them when we had to replace our old halogen light fixtures to IKEA's new LED. It turned out that the old hole was too small for these new, so it could not just push them up in the old hole. irritated by this, I thought that then you have to screw them on the cabinet ceiling. But surprised again, it turns out that the screw holes in the new armature is tighter than the hole is. The hole is in this case too large. So what do you make of this mistake from IKEA. Well you're happily owner of a 3D printer. so it was just to sit at the computer and make a suitable adapter. The results presented here work perfectly, made for IKEA's cabinets 16mm thick shelves.