43mm ND4-ND64 (2-6 Stop) Variable ND Filter and CPL Circular Polarizing Filter 2 in 1 with 28 Layers of Anti-reflection Green Film, Two Orange Levers, Imported White Cloth Nano-X Series - KENTFAITH
How to make a film pack ND filter for your Polaroid SX-70 | Polaroid photography, 600 film, Film photography
Zenit H-4x 77x.75 ND Filter for Krasnogork-3 K3 16mm Super 16mm Film Camera | eBay
Anti-Reflection Coated Optical Uncoated Laminated Neutral Density (ND) Filter Film - China UV Filter, Neutral Density Filter | Made-in-China.com