This is the EXPS3-0 model

This is the EXPS3-0 model

This is the EXPS3-0 model, as the title and description on this page don't exactly make that clear (as of 08/2011).

The big plus for the XPS series is the size, using only one CR123 battery. The downside is the lower runtime, although most modern black rifle pistol-grips and buttstocks have space specifically designed to hold extra batteries.

The other main strength of this model is the quick detach mount and it really is a breeze to take the sight on and off. According to the spec sheets, the quick detach mount is no worse than the normal mount for return-to-zero performance. However, the shorter single battery models show 2 MOA return-to-zero rather than 1 MOA of the longer 2 battery models.

The quick detach mount also means this model sits a bit higher than the regular screw-on mount. I personally wanted this, as I didn't want the fixed A2 front sight on my AR co-witnessed with the holographic image. The backup iron sights are still viewable in the lower 1/3rd of the lens, and if an unobstructed view is necessary the QD mount makes that easy. 

This is the EXPS3-0 model