Fotodiox Pro 6.6x8.5" Graduated Neutral Density .6 (Grad-ND4, 2-Stop) Hard Edge Filter (works with WonderPana 66 Systems)

This filter provides up to a 2-stop reduction of light in selective areas and is constructed from optical polycarbonate for clarity and durability.

• The description claims the filter is the strongest in the industry at 2mm thick.
• The description claims the filter is practically unbreakable.
• The description claims the filter is guaranteed spectrally neutral to within ±3 in the a and b channels of the lab color space.
• The description claims the filter is guaranteed to be within ±2 in regards to total light transmission.