Amazon.com : Polaroid Optics 40.5mm 3-Piece Filter Kit Set [UV,CPL, Neutral Density] includes Nylon Carry Case – Compatible w/ All Popular Camera Lens Models. : Electronics
Handmade ND Filter for SX-70 Cameras Use Polaroid 600 Film - Etsy
Gear Review: Polaroid Variable ND Filter | LG Visuals ⎟ Lewis Gething Visuals Blog
These ND-filters have been out of stock for an eternity... Any cheap alternatives for 600 film in SX-70? : r/Polaroid