My favorite ND filter for fast Leica lenses! | Steve Huff Photo
Heliopan 67mm Variable Neutral Density (ND) Fader Filter - Newegg.com
Amazon.com : Heliopan 77mm Variable Gray Neutral Density Filter (707790) with specialty Schott glass in floating brass ring : Camera Lens Neutral Density Filters : Electronics
Heliopan Variable Grey ND Filter Slim (0.3 - 1.8) - 60mm (ES 60) – Camera Film Photo Limited #ENJOYFILM
Heliopan 77mm Variable ND 0.3-ND1.8 Lichtfilter Used 35mm SLR Film DSLR Digital | eBay