The 86mm Coarse Thread Streak 2mm Self-Rotating Filter from Tiffen is a special effects filter designed to render a single light ray from a point light source. This filter features a single series of etched lines spaced 2mm apart from each other, which run diametrically across the filter surface. This filter is set in a self-rotating mount, which can be used to adjust the orientation of the light ray to suit your composition or desired effect. It is constructed from clear optical-grade glass and mounted in an aluminum filter ring.