When it comes to choosing an overall shower curtain rail, there are lots of factors to consider. Some of the available materials include brass, stainless steel aluminum, and even some plastics.
However, what you need to consider before investing in a shower curtain rail is that bathrooms are steamy and wet environments, so one of the products that you should stay away from is mild steel. This is because they tend to rust quite quickly, meaning you'll need to replace them sooner than you think.
One way to test whether a shower curtain is made of mild steel, is to simply get a magnet and touch the surface of the rail with it. If the magnet sticks, then it's mild steel, and you should not purchase it.
The best alternatives to mild steel include brass, which is highly malleable and durable; stainless steel, which is highly resistant to rust, and corrosion; and aluminum, which is soft and malleable but also lightweight and very corrosion resistant. So our recommendation would be aluminum which is the most favorable all-rounder.