Countersunk head consists of a high quality nylon plug and a zinc-plated nail screw. Pre-fitted for quick assembly. Led through the component in a time-saving through-type installation. When driving in the nail screw, the fixing sleeve expands and anchors itself securely in the building material. Ideal for fixing timber constructions in all building materials in internal areas. Integral setting lock prevents pre-expansion. Rigid reinforced collar. Saw-tooth threaded screw.