The front of the filter allows screwing in other filters. The front size is one size larger than the back's. For example, if you get the 67mm filter, you need a 72mm filter to add into the front of it. Use the rotation lever to adjust the ND (Alignment of a number and the line); Rotate the outer frame to adjust the polarization angle. Aluminum Alloy Frame The Haida filter's frame is ultra-slim aluminum alloy ring ensures durability while allowing the filter to remain lightweight. The thin, aluminum-alloy filter ring minimizes the potential for vignetting, while remaining durable and lightweight. Waterproof To prevent internal ghosting and reflections, the glass features eight layers of multi-coating. These coatings also offer greater protection to a filter substrate and help it to stay clean for longer than with uncoated filters.
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