The4 x 5.65" Streak FilterfromTiffenis 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 apart from each other (filter comes in space options of 1mm, 2mm, 3mm), which run acrossthe filter surface (diagonally or horizontally, based on filter option purchased) . When the filter is rotated, the orientation of the light ray can be adjusted to suit your composition or desired effect. The filter is constructed from clear optical-grade glass for maintained image clarity and measures 4 x 5.65" / 101.6 x 143.5mm.