Hoya 77mm / 77 mm Variable Density (ND3~ND400) Filter - NEW | eBay
Amazon.com : PROfezzion 77mm Variable ND Filter, ND2-ND2000 [1 to 11 f-Stop] ND Filter for Canon EF 16-35mm f4L /Sigma 24mm f1.4 DG HSM/Nikon AF-S 20mm f1.8G ED Lens/Other Lenses with 77mm
Amazon.com : NiSi 77mm Swift True Color ND-Vario | 1-5 Stops Variable Neutral Density Filter | Adjustable ND, True-to-Life Color, No Vignetting, Optical Glass with Nano Coating | Photography and Videography : Electronics