Lyman Receiver Sight for Marlin 336 (3662215)Lyman 66 Receiver Sights are used with flat receivers. They feature 1 4 minute audible click micrometer windage and elevation adjustments as well as coin slotted low profile stayset knobs. The quick release slide with return to zero preset screw allows quick removal and replacement. Includes two interchangeable aperture discs: a large hunting aperture and a small target aperture. Black anodized aluminum body with blue steel knobs and detents. Receiver