It's a high-quality 4x4" Nano Infrared Neutral Density 1.8 (6-Stop) Glass Filter, expertly crafted by the reputable brand, NiSi. This durable and effective filter is designed to significantly reduce the amount of light entering your camera lens, enabling the use of a wider aperture and slower shutter speed even in bright conditions. This innovative filter is optimized for high-definition 6K digital cameras, making it an essential tool for professional cinematographers. It features NiSi's exclusive dual-sided Nano coating technology, which not only controls infrared light pollution but also ensures ultra-low color shifting, providing superior color control compared to other leading competitors. Constructed from a single piece of optical glass, this versatile filter offers an anti-reflective coating that effectively reduces glares and reflections. This ensures a 6K digital image delivery with no loss in clarity, enhancing your photography experience.