Hexalobular socket flat head screws with special low head

It is a work that must finish lightly and beautifully (including rust prevention). This time we will also use it in the production of racing cars active overseas. Although how much container transportation is done, rust caused by moisture, salt damage, etc. on the ship is terrible. I would like to align both size and length, but since it will be a considerable stock risk, I will purchase the size I often use at the time of special price. · · · I need a special wrench, but it seems to be useful for theft.