C-AF 2XII TELEPLUS can make the focal length of all the for Canon EF lens increased to 2 times,and the auto-focus function of the original camera lens can be used perfectly, and don't change the EXIF information.

Compatibility:
C-AF 2XII is only compatible with fixed focal length L-series lenses 135mm and over, as well as the EF 70-200mm f/2.8L, EF 70-200mm f/2.8L IS, EF 70-200mm f/4L, and EF 100-400mm f/4.5-5.6L.

Features:
Compatible for Canon EF Mount Lens(not for Canon EF-S lens).
Can increase the original lens focus length to 2 times.
Support lens Auto Focus function and won't affect to Exif information.
Adopt 7 optical glasses, 4 groups, the depth of field is half of the original lens.
Good helper for long distance photography.
With upgraded USB firmware interface.

Specifications:
Mount type:Canon EF-Mount lens
Magnification:2 times
Depth of Field:Half of the original lens
Min stacking focal length:Equal to the original lens
Constitution of the lens:7 glasses, 4 group
Focus mode:Auto focus
Lens Coating:Multi-coated
Exposure factor:Approx. 4 times (equal to 2 aperture )
Diameter and length:Approx. 68×51mm
Weight: Approx 154g
Color: black

Package Listing:
1 x C-AF 2X II TELEPLUS Adapter
1 x Product Manual

The 2X Teleconverter can make the focal length of all the Canon EF lenses increased to 2 times, Built-in 4 groups, 7 pcs optics, and the exposure factor enlarge approx 4. (equals to 2 aperture).
Compatible for Canon EF Mount Lens.[Notice:It only compatible with fixed focal length L-series lenses 100mm and over, as well as the EF 70-200mm f/2.8L, EF 70-200mm f/2.8L IS, EF 70-200mm f/4L, and EF 100-400mm f/4.5-5.6L.]
Support lens Auto Focus function.Outstanding image quality thanks to new optical design and improved AF performance. The focus speed is really fast and can track the subject, and lock the subject flexibly and accurately.
Lens coatings are optimized to minimize ghosting and flare. With the aperture adjustment lever on the adapter, you can adjust the aperture fast.
With an upgraded USB firmware interface, it supports USB firmware upgrading, and through subsequent upgrades, the adapter can improve its function, and fix bugs.