Theon Sensors has developed the NX-135B clip-on afocal night vision attachment for mounting on top of optical day sights and Laser Range Finders (LRFs) to provide night vision capability. It provides observation, target acquisition and aiming capabilities during night time or low light conditions by intensifying the available light of the nocturne sky.

The afocal night vision sight is mounted on top of the day sight via a dovetail mounting bracket interface. Due to its exact factory set 1X magnification, the sight mounts on Laser Range Finders (LRFs) and day sights without affecting their boresight settings. The user continues to operate the day sights as usually. Reticle readings, eye relief distances and shooting/observation practices remain the same as in day time.

The sight features the largest focal length objective lens in this class of instruments, thus providing increased recognition and identification ranges and a field of view which is a better match to the field of view of most LRFs and large magnification day sights.