The Certified model has passed mil-spec testing for water proofness, drop test, etc. and comes with the flattop adapter. Battery life on both units is 7 hours continuous on the highest setting.
Here's some further info I copied of Leupold's site :
A multifunctional optical scope for tactical firearms, the Mark 4 CQ/T combines the strengths of a red dot sight and a variable-power riflescope. At 1x it functions as a non-magnifying illuminated sight for use at close ranges. With the true 1x setting the scope can be used with both eyes open, allowing the user to maintain a wide view of the area. The clear, bright Circle Dot reticle serves as a bold aiming point, helping to ensure fast acquisition of small target areas in close, quick encounters.
At 2x or 3x, targets can be accurately engaged at medium ranges in urban or open terrain. The dot is sized to help ensure fast target acquisition, and the circle’s edge can be used to lead targets at long distances.
The Mark 4 CQ/T can be employed on tactical firearms such as the M16 and AR-15. It mounts to MIL-STD-1913 (flat-top) rail bases
(with optional mounting hardware), M16s and AR-15s with handles, and similar firearms. The scope’s compact configuration – 8.75
inches long (at zero diopter) and 17.5 ounces in weight – helps the user to initiate action quickly in an emergency situation, yet adds
minimum extra weight or bulk to the weapon.
Specialized eye relief, optimized for the M16 variant cheek weld, permits mounting of the scope in the preferred middle receiver position
so the user maintains correct head position with short-stocked firearms.
The illuminated Circle Dot reticle can be used day or night. It is fully visible without illumination for daytime shooting. Ten illumination settings provide good contrast between the aiming point and targets in virtually any light conditions without overwhelming natural low-light vision. Two low-intensity settings are compatible for use with night-vision equipment. Illumination power is provided by an AA battery, which can be quickly and easily replaced in the field without tools.
Range estimating can be done by placing the target inside the circle of the reticle. At 3x the diameter equates to six feet in height at 100 yards. At 200 yards, six feet is measured from the dot to the edge of the circle.
Other features of the Mark 4 CQ/T include a large field of view for fast target acquisition and tracking of moving targets. Windage and
elevation adjustments can be made in 1/2 minute-of-angle (MOA) tactile & audible click increments.
The scope body comes with integrated MIL-STD-1913 rail mount cross slots, which enables the user to attach accessories such as a
laser designator, flash light or night-vision device.
The Mark 4 CQ/T is manufactured from rugged aircraft-grade aluminum with an anodized matte finish for “no glare” in daylight. It is 100
percent waterproof and designed to be salt, fog and chemical resistant. All exterior lens surfaces have DiamondCoat™ scratch-resistant
coating. All interior lens surfaces are coated with Multicoat 4® to maximize light transmission. Flip-open lens covers provide protection during transport and use in rough terrain or heavy brush.
For even more info click here www.leupold.com/pi_cqt.html