Stop the writing on your Canon 16-35mm f/4L IS USM lens from appearing in your underwater images with IKELITE ANTI-REFLECTION RING FOR CANON 16-35MM. It blocks the aperture, focal length, and other written information on the front element of the lens from being reflected in the interior of the dome port attached to your camera housing. Without the ring, these unwanted reflections could show up in your photos and videos. A self-adhesive vinyl surface enables easy attachment to your lens.