When a design engineer or architect chooses stainless steel for a particular purpose, he has an extensive number of different grades to select from. There are also various surface finishes to choose from. The decision as to what type of steel is best suited for any given purpose is based mainly on how corrosive the ambient conditions are. However, surface quality or surface finish also affects the sensitivity to corrosion, and its cleansability of dirt and bacteria, which is of particular importance in the food industry and health sector. Surface finish characteristics are therefore not merely question of appearance.