Dear Mr / Mrs,I am a buyer from ayuob gash located in Saudi Arabia. I am interested in this style of Top Hex Head Self Drilling Screw and in doing business with you.May I know more information about product such as:Head Diameter,Measurement system,Material,Do you have any quality assurance certificates?Hope you reply to all my questions so I could proceed with buying.Regards and thank youayuobayuob gash Show More