Cavision 28 to 37mm Threaded Step-Up Ring

This Cavision 28-37mm Step-Up Ring enables the use of 37mm threaded filters on lenses with 28mm filter threads. The 6mm depth enables this ring to fill the gap between the lens and the back of select rod-mounted matte boxes, helping to keep reflections from hitting your lens. The step-up ring has a 40mm outside diameter for use with clip-on matte boxes. It features a lightweight aluminum alloy construction with a black anodized finish.