Abstract: The present invention pertains to a screw comprising an enlarged head and a shank with threads. In particular, the enlarged head has a bottom surface comprising a plurality of ribs extended from the outer periphery thereof to the shank, thereby providing with a good resistance of extraction and a good waterproof effect. Additionally, due to the ratio of the outer diameter of the shank to the outer diameter of the head being 1:3.5˜5.5, the debris extruded out of the object hence can be covered and squeezed beneath the enlarged head, so as to maintain a clean appearance.

Abstract: A screw includes an enlarged head and a threaded shank longitudinally extending from said head; said head has a bottom surface with a plurality of ribs protruded therefrom so as to provide with high frictional resistance and waterproof effect when screwing in. Further, the ratio of the outer diameter of head to the outer diameter of shank is 1:3.5˜5.5. Accordingly the head has greater areas to cover the ejected debris of object so as to maintain clean appearance.