Stair treads can be of different lengths and widths. New side walls have to be made for different step widths than those listed in the catalogue and this means increased costs, which are reflected in the price of the stair tread. Therefore, standard widths should be used when designing the building and should be adhered to as far as possible. There is no restriction on the length of the stair tread, only static. Atypical stair treads can also include grates that are fitted with a non-slip tread edge, are mounted in frames and have the function of a stair tread. Stair treads are manufactured in both welded “SP” and pressed “P” versions.