Rawlplug® UNO® Plugs are truly universal plugs which fix into any wall, ceiling or floor. Suitable for use in: concrete, brickwork, stone, blockwork, plasterboard. They have a unique design with expansion throughout the length of the plug. They expand at the top giving instant grip. Anti-rotation features prevent spinning in the hole. Screw Head Size: Yellow: 3-4.5mm Red: 3.5-5mm Brown: 4-6mm Blue: 4.5-6mm Grey: 5-8mm Typical Applications: - Shelving and cabinets - Suspended ceilings - Switch boxes - Trunking and cable trays - Water heaters and radiators