I have confirmed the operation and shooting with the EOS R6 Mark II. With the combination of the EF 70-200mm F2.8 IS USM II + Canon EXTENDER EF 1.4x + Mount Adapter EF-EOS R, servo AF, high-speed H+, etc. worked without any problems, and I was able to take beautiful photos. This time, I accidentally purchased the same EXTENDER EF 1.4x, so I will be listing the cleaner one. The Canon EXTENDER EF 1.4x is an accessory that extends the focal length of a lens by 1.4x, expanding the range of photography. It comes with the box and lens caps (both sides)! - Brand: Canon - Model: EXTENDER EF 1.4x - Made in: Japan - Magnification: 1.4x, shoots without problems