Black Optex Zero Lens
On the Night Vision part, the american company "Black Optex" currently produces the Black Optex "Zero Lens", which is an optical alignment kit that enables the currently military-issued PVS-14 night vision monocular in front of a regular day optic, with a zero shift in point of impact.
As seen on the picture mounted in front of a BROWE 4x32 optic, it "allows the shooter to maintain the same shooting position, muscle memory, and eye relief with his primary sight," reports Soldier Systems.
It also features a quick detach mounting system, which enables rapid installation and removal of the PVS-14 from the weapon.
For more information visit: http://www.browe-inc.com/categories/BLACK-OPTEX-%252d-ZERO-LENS/