This is a copy of the old sights that Freund invented in the 1870's and 1880's. This particular model is made for round barreled Pedersoli Sharps rifles with a 3/8" front dovetail. The front sight has a contrasting color on the front edge to be seen easily. The rear sight has a diamond shape opening below the sight notch for better visibility during low light hours and to keep from canting the rifle. The staff can be flipped up for longer distances. These sights are shown in "Freund & Bro-Pioneer Gunmakers to the West" by Pablo Balentine, Item #FBPG in our book section.