Amazon.com : Heliopan 49mm Neutral Density 2x (0.3) Filter (704935) with specialty Schott glass in floating brass ring : Camera Lens Neutral Density Filters : Electronics
Heliopan Bay 1 ND 1.2 Filter (4-Stop) 710083 B&H Photo Video
Heliopan ships Vario ND variable filters in sizes from 55 to 82mm: Digital Photography Review
Heliopan 77mm Variable Gray ND Filter 707790 B&H Photo Video
Amazon.com : Heliopan 58mm Neutral Density 4X (0.6) Filter (705836) with Specialty Schott Glass in Floating Brass Ring : Camera Lens Neutral Density Filters : Electronics
Variable ND test: Heliopan vs Tiffen vs LCW mk II | CineD
Heliopan 77mm Variable ND 0.3-ND1.8 Lichtfilter Used 35mm SLR Film DSLR Digital | eBay
Variable ND test: Heliopan vs Tiffen vs LCW mk II | CineD
Amazon.com : Heliopan 55mm Linear Polarizer Filter (705539) with specialty Schott glass in floating brass ring : Camera Lens Polarizing Filters : Electronics