Formatt Hitech Canon EF 16-35mm f/4L IS USM Adapter Ring for 100mm Lucroit Holder

This adapter ring serves two purposes. First the adapter ring connects the holder system to the lens. Second, the front of the adapter ring features threads to allow for the attachment of a circular filter. This allows you to add an additional polarizer or ND filter deep inside the holder system near the lens. Lucroit adapters are milled from high-quality aluminum in Spain.