The EOTech XPS series of sights is the company's newest and smallest version of their holographic aiming platform.  These optics are impressively small, leaving ample room on your weapons rail for additional equipment, such as a magnifier, nigh vision or a comfortable space for back up irons.  The much smaller size is accomplished by the use of a single CR123 lithium battery along with various other advances that has allowed EOTech to significantly shrink their hologram technology into a tough miniature package.  Currently the XPS series has two main offering:

The XPS3 and

The XPS3.

As with many EOTech's each of these has the option of a few different reticle setups denoted by an appended number - XPS2-0, XPS2-1, XPS2-2.