This sight has a special hard-anodized surface and the specification for water tightness is equivalent to a depth of 75 feet. The high quality requirements are designed to cope with frequent professional use on those types of guns that are typically used by the police and the military or for hunting under extreme conditions. The CompML2 is a day sight and is therefore not compatible with Night Vision Devices (NVD). For night vision compatibility, look for the CompM2 model instead. In all other aspects, the CompML2 and the CompM2 are identical. FEATURES- Unlimited field of view Parallax- free No centering required Day sight only Unequalled light transmission CETechnology giving up to 10 years of use on one battery Increased aiming confidence Submersible to 25 meters (70ft) No radioactive components Unaffected by sub-zero temperature ARMS mounts available