SC1020-Z Zoom Gear ~for Sigma AF10-20mm F4-5.6 EX DC HSMFocus gears allow access to the mechanical zoom function of many lenses. Use of these gears may require specific port extensions and may not be available for all housings and lenses. This focus gear is specific for the Sigma 10 20mm F4 5. 6 EX DC HSM lens. This item is non returnable, non refundable, non cancellable, and may be subject to extended lead times as it is manufactured on demand. We always do our best to meet trip deadlines so please advise