Countersunk hex socket screws according to ANSI B18.3 standard with UNC and UNF inch threads, in stainless steel A2 and A4. The countersunk head allows the screw to sit flush with the surface after installation. The design is similar in form to ISO 10642 but uses imperial dimensions and inch thread systems. This category contains subcategories for both coarse thread (UNC) and fine thread (UNF) variants in A2 and A4.