The aluminum body is carefully polished by hand to a glossy finish and it is not coated with any protective layer. This is done purposely because aluminum is a stable material under indoor condition, it will not oxidize easily. Even after months or years that the aluminum surface starting to become dull, it can easily be buffed away using metal polishing compound. After polishing, the product will look like new again. Re-polishing is not possible if the product is coated with a protective layer.