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 pictures. 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 the 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 - Country of Manufacture: Japan - Magnification: 1.4x, shoots without any problems