Original U.S. WWII Era M4 Collimator Sight With Leather M14 Carry Case - As Used on 60mm and 81mm Mortar Systems. Its in really good condition ! What you see is what you get !

This is a fantastic example of an M4 Collimator sight with an equally nice leather M14 carry case. This sight was used on both the US 60mm and 81mm mortar systems. By laying the sight on aiming stakes, the mortar squad could fire indirect missions. The open sight allowed the squad to fire direct lay missions. A collimator sight is a type of optical sight that allows the user looking into it to see an illuminated aiming point aligned with the device the sight is attached to, regardless of eye position (with little parallax). They are also referred to as collimating sights or "occluded eye gunsight" (OEG).

The basic layout of a collimator sight is a closed tube with a lens at its open end and a luminous reticle mounted near the closed end at the focus of the lens, creating an optical collimator. The reticle is illuminated by an electronic light source (an incandescent light bulb or, more recently, a light-emitting diode) or by ambient light gathered behind the reticle via an opalescent window or fiber optic light pipe. Collimator sights are a relatively old idea, being used in many forms for almost 100 years.