The surface finish of Hardened and Tempered Steel Strip products is not too critical in general engineering applications where the normal blue black (also known as blue grey) oxidised finish from the heat treatment is satisfactory. By control of the atmospheres in the furnaces non-oxidised surfaces can also be produced, on a selected basis, and alternatively, steels can be satin or bright polished where needed, these finishes being as much for cosmetic reasons as for engineering purposes.