Aluminum – The aluminum wall louver is lower in cost, weight and easier to maintain. Also, it doesn't rust or corrode. Not as durable as stainless steel but still suitable for most environments.
How durable are aluminium louvres?
Durability of Aluminium Louvres
Despite a substantial difference in weight compared to copper or steel, aluminum is one of the sturdiest materials that can be used, so its lightweight property combined with its durability gives it a high strength-to-weight ratio.