The NiSi PRO Protection 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 Protection filter allows 99.3% of light pass through it. The frame is made of high quality aluminum with thickness of only 5.2mm. Additionally, superfine dull polishing and elaborate knurling make sure that the frame will not blanch because of repeated rotation. The ultra thin filter frame helps to help avoid vignetting on super wide angle lenses.