NiSi Cinema 4×5.65” True Color Linear Polarizing Filter | NiSi Optics USA
Amazon.com : Vizelex Polar Throttle Lens Mount Adapter - Canon FD & FL 35mm SLR Lens to Micro Four Thirds (MFT, M4/3) Mount Mirrorless Camera Body with Built-in Circular Polarizing Filter :
Vizelex Polar Throttle Lens Mount Adapter - Canon EOS (EF / EF-S) D/SL – Fotodiox, Inc. USA
CIRCULAR-POLARIZING LENS (46mm-82mm) – Official 7Artisans Store