Amazon.com : Tiffen 77VND 77mm Variable Neutral Density Filter for Camera Lenses, Black : Camera Lens Round Filters : Electronics
PRO 77MM Variable ND Extreme - HGX Prime (5.3-12 stops) - Looking Glass Photo & Camera
NiSi 77mm ND-VARIO Pro Nano 1.5-5stops Enhanced Variable ND - Jim Patterson Photography
7artisans Mc Vnd Filter Neutral Density Filter 1.5-8 Stops Adjustable For Camera Lens 58mm 62mm 67mm 77mm Variable Nd Filter - Camera Filters - AliExpress
Singh-Ray 77mm Vari-ND Variable Neutral Density Filter R-86 B&H