This TangoDown Light Portal Front Sight allows one to mount a weaponlight just below it without both being an obstruction to each other... "The FFA-02 allows a weapon light to mount on a carbine where it should… forward on the 12:00 rail. The road block in the past was where to mount a light without blocking the front sight, or placing the light in a less-than-optimum position on the weapon. Problem solved- we combined the two into one tough package.