ANSCO's high quality socket screws

Commonly known as flange bolt. As the name implies, it is a hexagon bolt with a flange (flange) on the head. The feature is that it is not necessary to install a washer (cost reduction), and you can prevent forgetting to install a washer. Since the seat surface is wider than that of normal hexagon bolts, it is hard to loosen and also prevents the mating member from sinking.