The Hobsons X9 Class 3 Countersunk Square Screw (#10-24 x 50mm) is a premium self-drilling fastener designed for secure metal-to-metal fixing where a flush, professional finish is required. Featuring a countersunk square drive head and Class 3 corrosion-resistant coating, it provides reliable performance for sheet metal fabrication, electrical work and general construction in indoor and protected outdoor environments. The #10-24 fine thread and X9 self-drilling point deliver strong holding power and fast installation into light gauge steel without the need for pre-drilling in most applications. Supplied in a convenient 500-piece box, it is an ideal choice for trade professionals requiring strength, efficiency and a clean finished appearance.