A stair nosing is the finishing edge of your stair treads with an overhanging edge required by code to provide more surface area for safety. Stair nosings are available from majority of flooring manufacturers to match their products but are very limited in profiles and design.
Although manufacturer provided matching stair nosings are convenient and for the most part match the color and design of the flooring, they may not work in more complex applications and look very basic. Most pre-manufactured nosings come in 2-3 inch widths which is noticeably narrower than most flooring products on the market today. Custom fabricated nosings provide a more elegant look with more options for profile designs. They can also be made from the flooring you are actually installing resulting in a more seamless look. Depending on the material, irregular shaped stairs can prove to be challenging to install but fabricated nosings can be made from more pliable materials and finished with a thinner layer matching the species of wood of your flooring products.