Amazon.com : Schneider Optics 4 x 5.65 inch Graduated Neutral Density 0.3 Filter, Soft Edge with Horizontal Orientation : Camera Lens Neutral Density Filters : Electronics
Neutral Density Graduated Filters (ND Grads), and ND Standards in Resin from LEE Filters
World's First Variable Graduated Neutral Density Filter | PowerGXND