Hoya's ProND Graduated Filters let you darken landscape skies without a separate filter holder - DIY Photography
Hoya 77mm HD3 UV Filter - With Hoya 77mm Variable ND Filter (0.45 to 2.7 (1.5 to 9 stops) , Cleaning Kit - Walmart.com
Hoya 72mm HD3 UV Filter With Hoya 72mm Variable ND Filter (0.45 to 2.7 (1.5 to 9 XHD3-72UV ND
HOYA | Variable Density II
Zomei Fader Variable ND Filter Adjustable ND2 to ND400 ND2 400 Neutral Density for Canon NIkon Hoya Sony Camera Lens 49/52/55 mm|nd2 to nd400|neutral densityfilter nd - AliExpress
Hoya Round 77mm Variable ND filter | Angel Films | Equipments, Studios, Crew for Hire