This is a slightly used CMO M-16 Marksman Elite w/ carry handle mount. In excellent condition - almost new, except for just a bit of wear on the base (where it sits in the top of the carry handle). 4x power, 21mm objective.
The illuminated post reticle is powered by a single small CR 2032 camera battery (fresh battery included). The bullet drop compensator is designed to be easily adjusted for ranges out to 500 meters (based on a 20" barrel, 62 grain bullet, but I've used it on a 16" barrel, 55 gr bullets, with good results). A fantastic scope for medium-range plinking and shooting prairie dogs / varmints.
Edited to add: Also comes with a 'non-powered' cover which replaces the battery, and includes a translucent plastic 'skylight' which I guess is supposed to gather sunlight , but obviously isn't quite as effective when it's near dawn or dusk :)
This scope has been out of production for a while, but here's a link to the original review on AR-15.com:
Another 'vintage' discussion: thread on the scope