When building stairs you will use quite a few of them nailing the treads, landing and risers. A 8d nail is two and one half inches long. They come in commons, galvanized, bright and sinkers. If you are using them outside you will want to use the galvanized nails. Inside you will want to use 8 sinkers but feel free to use the galvanized because they do actually have a greater holding power than sinkers.