These are very nice individually wrapped 7x50 right Bausch & Lomb prism assemblies. These have a pinkish/purple anti-reflective coating. This prism assy. will fit most of your 7x50 Mark models. The manufacturers part number is 29422-23. Well made mounted two prism erecting assembly is what you need for building a spotting scope or monocular. Two mounted porro prisms, 2 inches long by 1 inch high. Assembly is 2-1/2 inches thick by 2-1/2 inches diameter and the view openings are 1 inch diameter.