What is the difference between anodised and non-anodised aluminium profiles?

Anodised profiles are coated with a protective layer, an electrolytic oxidation process that increases the thickness of the natural oxide layer on the metal surface. This layer helps protect aluminium from corrosion, wear and tear and gives it a longer life. Unanodised profiles are not coated with any protective layer, making them more susceptible to corrosion and wear.