This is the just released EF to R lens adapter which includes the Cir Pol-Great for those lenses that need a large filter adater at the front like the 11-24 zoom 14mm prime or your long teles i.e 400mm F2.8 500m F4 etc etc
Extending the range of compatible lenses, this Canon Drop-In Filter Mount Adapter EF-EOS R is a unique lens adapter designed for attaching any EF or EF-S-mount lens to the EOS R mirrorless digital camera. This sophisticated adapter affords compatibility with select A-type drop-in filters, and includes a circular polarizer filter to help increase saturation and contrast and reduce reflections.
The adapter's design extends the ability to use filters with unique lenses that cannot accept filters on the front, and and it also retains full autofocus and image stabilization capabilities of the mounted lens. It is also dust- and water-resistant, making it suitable for use in harsh weather conditions.