This sight is a Lyman ORIGINAL with the stamp on the rear of the sight. This No 16A is the lowest Lyman made, and has one fold leaf that allows adjustment from .400 to 0.500 inches. Single adjustable blade, held in place by two screws, is reversible providing either a V notch or a U sight notch. This is a perfect auxiliary sight for scope-mounted rifles. The white triangle makes sight alignment fast. This popular sight folds close to the barrel when not in use. Designed to fit 3/8" dovetail slots.