For instance, alloy 304 is used to make flag poles that will be used in normal conditions.
However if the environment you will erect the flag pole in is corrosive to metals, look for a pole made of alloy 316.
You may want to check the wind load of any flag pole you are interested in purchasing. You will also want to choose a finish.
Do you want a ground set pole or a wall mounted vertical or outrigger flag pole? Did you know that you can buy a roof mounted flag pole or a tilting stainless steel pole counterbalanced with a hinged base?
Choose a finial such as a spear, ball or eagle to give your flag pole the look you want. What is the height limit your are looking for and the halyard system you prefer? Choose either an external halyard system for raising and lowering the flag or an internal system which has a door in the pole which can be locked to prevent mischief to the flag.
Decide on the above ground height you want the pole to be. You can get flag poles from 20 to 80 feet, with the actual length of 23 to 88 feet.
Aluminum flag poles are most often chosen but I would suggest a stainless steel flag pole for strength and appearance.
Also stainless steel is eco-friendly and can be recycled, melted down and used to make something entirely different. Usually extremely tall flag poles are used at government facilities.
Stainless steel is durable and can be cleaned with a mild dish soap and a soft cloth. Sometimes you can just hose the pole to remove mud and bird droppings, however if you have a super tall flag you will have to let mother nature clean the flag pole.