When I first purchased this, I was not impressed. It did nothing. However, I read Aimpoint's instructions and it states that the filter can be rotated 180* to provide varying effect. I did not see how this was possible, given that the filter is a plastic lens embedded in a rubber insert that is pressed into the ocular of the Comp series Aimpoint. Rotating the lens meant just rotating the rubber housing in the ocular. Anyway, today I tried it, and...WOW!



*Cameo by "Big'un" at 3:50