These nylon wall plugs are intended for use in hollow walls and consist of 2 sections. When the screw is tightened, the back part of the plug is folded double towards the front of the plug. Another variant is the butterfly plug. This has 4 ‘wings’, and is ideal for mounting in shallow holes. You can use these wall plugs for hanging paintings, light mirrors and other light items. This kind of plug gives a strong grip in plasterboard and similar materials.