This Cavision 72-82mm Step-Up Ring enables the use of 82mm threaded filters on lenses with 72mm filter threads. The 9mm depth of this ring provides more surface area than a standard step-up ring. This provides a more secure grip to the clamp of your Cavision Clamp-On Matte Box. The step-up ring has an 85mm outside diameter for use with clip-on matte boxes. It features a lightweight, aluminum alloy construction with a black anodized finish.