Canon Drop-In Filter Mount Adapter EF-EOS R with Variable ND Filter Question

[MIAMIPHOTO]

Is there anybody using EF lenses with Canon mirroless?
Do you have the Canon Drop-In Filter Mount Adapter EF-EOS R with Variable ND Filter?
1. Any experience with it? Can you take out the filter and tape the filter hole and use it as a regular adapter when you don't need the nd filter?
2. They are selling third party versions? Any luck with those?

 

[Canon brook]

Have one with the polariser and like it a lot….saves putting the Lee filter set up on the front….will possibly look at the HD filter as my next purchase……I usually leave the filter in or on odd occasions switch to the non filter adapter….However I’m sure I saw a copy of the filter housing on eBay…it has no glass in so just acts as a seal / dust preventor when you don’t want the complete filter in…….