Amazon.com : Meike MK-EFTR-C VND Drop-in Filter Auto-Focus Mount Lens Adapter for Canon EF to EOSR with Variable ND Filter and UV Filter for EOS R R5 R6 RP R7 R10 C70
New Kipon EF to E-mount electronic adapter with variable ND filter is in Stock at Adorama and Amazon US/DE - sonyalpharumors
Introducing the Tilta Electronic Neutral Density Filter (TE-ND) for RED DSMC2 - YouTube
Uv Nd Filter Neutral Density Filtors Cover Lens Protective Protector For Yi 4k Ii Lite Action Camera Accessories - Sports & Action Video Cameras Accessories - AliExpress
My Prototype Electronic Variable ND Filter - Cameras - EOSHD Forum