The outer diameter of Cooke S4/i Mini prime lenses is 87mm. Though this outer diameter is not included in the ranges of our Zip Boxes, there are two workarounds. One option is a rubber step down ring that we can provide upon request. This is a thick black rubber band that can be used with the 90-95mm version. Alternatively, you can use a pair of right angle wire cutters to snip back the rubber teeth of the 80-85mm version. This option is less visually appealing, but you won't have to keep the additional rubber ring in your kit.