This Cavision 58-72mm Step-Up Ring enables the use of 72mm threaded filters on lenses with 58mm filter threads. The 10mm 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 a 75mm outside diameter for use with clip-on matte boxes. It features a lightweight, aluminum alloy construction with a black anodized finish.