Description: Size : M3.9 / #7 Length : 9.5mm~75mm Material : Carbon Steel / Stainless Steel Point type : Drill point and sharp point Attachment : W/WO Wing Surface Treatment : Zinc plated, Yellow Zinc plated, Black zinc, Zinc Nickel, Mechnical Galvanized, Ruspert?Slat Spray Test according to customer requirement. Standard : DIN, IFI, JIS, according to customer's drawing Package : Bulk packing, Box packing, Bag packing, Blister Flat head window screw characteristic : The advantage of flat head can drill whole head into object, the head of screw doesn't protrude on object. It is used normally in contacting fastener face of object and let object surface smooth. Flat head window screw used in window construction, considering in appreance, it often uses flat head type to make head of screw will not protrude on object.