tysonsadler 0 Posted May 23, 2020 Nauticam C1635II-F Focus Gear (19542) Use with 21270 Focus gears allow access to the mechanical manual focus function of supported lenses. Use of this gear may require the use of additional port extensions or adapters. Check the Port Chart for more details. This focus gear is for the Canon EF 16-35mm f/2.8L II USM (for use with 21270 Extension Ring 70 with Focus Knob) lens. $240 or reasonable offer Share this post Link to post Share on other sites