Tiffen 77mm ND 0.6 Filter (2-Stop) 77ND6 B&H Photo Video
77mm Indie Pro Infrared/Neutral Density Filter Kit - W77INDPROKT – The Tiffen Company
Amazon.com : K&F Concept 77mm Variable ND Filter ND2-ND32 Camera Lens Filter (1-5 Stops) No X Cross HD Neutral Density Filter with 28 Multi-Layer Coatings Waterproof : Electronics
dHD Digital Brands Variable Fader ND2 - ND400 Filter 77mm Grey Filter 77 MM | eBay
Hoya SOLAS 77mm Variable Neutral Density Filter, 1.3-stops to 8.7-stops XSL-77VDY