A type of screw which cuts its own thread into a pre-drilled surface (sheet metal or plastic, for example) and gives grip, therefore not requiring to be tightened from the other end. Ideal where only one side can be accessed. Generally used to attach a component to a surface. Cross recessed drive. Countersunk head gives a flush finish once in place. AB (sharp) point. Conforms to BS4174. Bright Zinc Plate (BZP) finish offers resistance to corrosion.