The aluminum coil has appropriate climate resistance, with general thickness of oxide film (three μ m) will not change color, corrode, oxidize or rust in indoor use for a long time. The aluminum coil with thickened oxide film (10 μ m) may be used outdoors, and may be uncovered to sunlight for a long term without discoloration. https://aludepot.com/product/3105-aluminum-coil/