The NiSi HUC Protector filter is designed to provide the best protection from dust or impact to the front element for camera lenses. Made from high-quality glass with nano coating on both sides, the NiSi Pro Nano HUC protector filter allows 99.3% of light pass through it. The frame is made of high-quality aluminum with a thickness of only 5.2 mm. Additionally, superfine dull polishing and elaborate knurling make sure that the frame will not blanch because of repeated rotation; this ultra-thin filter frames to help avoid vignetting on super wide-angle lenses