EOTECH’s XPS and EXPS holographic weapon sights are their latest holographic reflex optics. They are more modern than the older 512s and 552s, reducing the profile of the optic and integrating enhanced circuitry and functions. The XPS model is the standard-height with a fixed base mount. The controls are on the rear of the optic. The EXPS models incorporate a riser with a QD mounting system. EXPS sights put their controls on the left side of the optic, so users can easily reach up and control it with their forward hand. Aside from the mount and button position, there is no real major difference between the two optic systems. When shopping these optics, you will find that they have a numeric designation, such as the XPS2-0, or the EXPS3-4. These numbers are an important indicator of features and reticle. The first number will be either a 2 or a 3. The 3 models have a NV-compatibility button that will instantly lower the reticle brightness for night vision devices. The 2 models do not have a night vision setting. The second number can be a 0, 2, or 4. This number will tell you how many aiming dots are in the reticle. A ‘-0’ model will only have the single center dot. A '-2' model will have a two-dot reticle that can be used as a holdover for long-distance shooting. The '-4' models will have a four-dot reticle that has various BDC holdovers. Reticles with multiple dots are best used with a magnifier, as the dots may difficult to discern with the naked eye. Once you’ve memorized the EOTECH naming convention, it is easy to find exactly the unit you’re looking for. For example, if you want a QD EOTECH with night vision compatibility and a single-dot reticle, you know to search for the EXPS3-0.