FotodioX's 6.6x8.5" Graduated Neutral Density 0.9 Hard Edge Filter for WonderPana 66 Systems is one of the strongest in the industry at 4mm thick. This filter is practically unbreakable and is guaranteed spectrally neutral to within + or - 3 in the a and b channels of the lab color space. This filter is also guaranteed to be within + or - 2 in regards to total light transmission.
- Premium grade optical glass filter
- High Quality, super thick, multi-coated graduated filter