DIN 7972-C flat head sheet metal screw with slot (form C), ST3.9 x 50, Article number 7972C390501. Property class / material: ch, surface finish zinc plated. Flat Head Sheet Metal Screw with Slot manufactured to DIN 7972 with ISO 1478 tapping screw thread (ST) thread, coarse pitch, fully threaded. Standard parts to the same standard, property class, dimensions and surface finish are interchangeable between manufacturers; confirm the controlling standard revision, any class-society or application approval, and the mating thread before substitution.