Amazon.com : Tiffen 77mm Variable Neutral Density Filter 77VND for Camera lenses & Large Belt Style Filter Pouch for Filters 62mm to 82mm : Electronics
Best variable ND filter - Camera Jabber
25 Camera Lens Filters (Tiffen, Hoya, ProOptic, Quantaray, B+W and more) $900+ | eBay
Variable ND test: Heliopan vs Tiffen vs LCW mk II | CineD