Hoya 77mm Variable Neutral Density ND3-ND400 ND DSLR Digital Filter A- – EventCameras
Zomei 72mm Fader Variable Nd Filter Adjustable Nd2 To Nd400 Nd2-400 Neutral Density For Canon Nikon Hoya Sony Camera Lens 72mm - Camera Filters - AliExpress
Neutral-density filter - Wikipedia
Hoya 77mm Variable Neutral Density II ND3-ND400 Digital Filter **NEW D – EventCameras
Hoya 52mm Variable Neutral Density 3-400 Filter for sale online | eBay