Reduce the intensity of light to suit your need by placing the Arri Scrim - Half Double for Arrilite 600 in front of the light source.There are two metal screens mounted on a metal frameThis 5" half double scrim covers half the surface of the light bulb and reduces twice as much of the light beam intensity as the half single scrim or half as much as the full double scrimIt is designed for use with the Arrilite 600 bulb