Overview
The sight is water-tight down to 25 meters and runs on one 3-volt Lithium battery type 2L76 or DL1/3N. The aiming dot's brightness is adjustable for better visibility and increased battery life.
The M68 is parallax-free at around 50 yards, meaning that the red dot will not change position based on eye position at that range. At shorter ranges the point of aim will change position based on eye position with the maximum error being equal to the diameter of the sight's optical window at short range.
The CompM2 is used across branches of the U.S. Armed Forces, Sweden, and various NATO countries, among them Norway. A variant known as the ECOS-N (NSN: 1240-01-495-1385) is also issued as part of the U.S. SOPMOD kit. The sight is also available on the civilian market and is employed by various law enforcement organizations (especially for SWAT type situations that involve close quarters work) and by recreational shooters.
The CompM2 is often faulted for its short battery life when the dot visibility is set too high, which is necessary for bright environments. The On/Off/Visibility knob is also prone to turning unintentionally when the weapon is stowed or retrieved, such as when mounting and dismounting vehicles. Batteries often burn out due to unintentional engagement of the sight's power. Large rubber bands are sometimes used on the sight to keep the knob from turning accidentally. Aimpoint's successor to the M68 (the CompM3) claims a single battery will provide 50,000 hours of operation on brightness level 7 out of 10. Aimpoint's newest military sight, the Aimpoint CompM4, has a claimed ability to operate continuously for 8 years or 80,000 hours on a single AA battery.
Read more about this topic: Aimpoint CompM2