These forgefix phillips single thread drywall screws have a black phosphate finish for increased durability the screws come complete with a phillips no2 insert bit their bugle head allows the screw to sink effortlessly into the dry lining without the need for countersinking which in turn minimises the damage to the surface applicationdesigned for fitting dry linings to studding phosphate coatings are made up of thin crystalline layers of phosphate compounds that adhere to the surface of the fixi