The NPZ PSU 1x/4x switchable zoom optical gun sight is the only switchable zoom prism sight alternative to the famous ELCAN Specter DR 1x/4x dual role combat sight. In our opinion, it is also every bit the sight that the ELCAN is while coming in at $900 less. Both the PSU and the ELCAN Specter DR use an internal 4x power magnifier at the front to cancel out the fixed 4x prism sight located at the rear part of both sights. The difference is that the ELCAN uses a rotating prism design for its built-in magnifier while the PSU has a sliding conventional lens in its magnifier part. Another big difference is that the PSU uses a common internal adjustment system, while the ELCAN has a non-standard and for many, unpopular, external adjustment setup. The PSU 1x/4x uses German SCHOTT glass for its lens and prism. SCHOTT optical glass is the best in the world and found only in the finest, high-end optics. When set to 1x magnification, the PSU provides a huge 26 degree field of view for rapid, both-eyes-open target engagement. When the magnification switch is flipped to 4x, the sight’s reticle is extended for range-finding out to 800 meters and comes in with a field of view a full degree wider than the ELCAN. The PSU is manufactured from a solid aluminum alloy body and is shockproof and watertight. The fully multi-coated optics are sharp and bright with accurate color rendition and excellent resolution. The PSU comes with a Mil-Dot style reticle or a BDC reticle. The BDC reticle provides ballistic compensation out to 800 meters and has a telemetric rangefinder in the lower right that provides height-based range-finding for a man-sized 1.8 meter target. The BDC is calibrated for the 62 grain M855 NATO round. The PSU’s reticle is illuminated by a single common CR2032 lithium battery and the illumination is not daylight visible but for use in dusk conditions. A definite BEST CHOICE! Compare the PSU to the ELCAN and you'll find the performance equal or better at a significantly lower price.