C815-F Focus Gear ~for Canon EF 8-15mm f/4L Fisheye USM (for use with 21230)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 8 15mm f 4L Fisheye USM lens (for use with SKU 21230 Extension Ring 30 with Lock). This item is non returnable, non refundable, non cancellable, and may be subject to extended lead times as it is manufactured on