This bracket holds a 41x44mm sea filter originally designed for a GoPro in place on a SJCAM 5000 underwater housing. These are designed to enhance photo and video in shallow water.
Note the strip of black lucite glued to the side and the screw holes in the bracket. I found that the bracket held fine with just friction but the option is there if needed. It is made from Taulmann 230 and created in TinkerCad