purchased the K&F Concept Nano-X PRO Series ND1000 77mm filter for my photography gear and I am delighted with the quality and performance of the filter. The frame of the filter is made of high quality brass material and features CNC pattern design, which greatly improves the hardness and flexibility. Installation was also very smooth and durable. The ND1000 filter reduces light by 10 f-stops, allowing longer exposure times without color cast or loss of image quality. The K&F Concept coating technology also gives the filter a very low reflectivity of 0.15%, which increases light transmission and reduces stray light and ghost images. The filter also features 36-layer double-sided nano-coating, which is waterproof, dirt-proof and scratch-resistant, which improves the durability of the filter. The frame is also very thin and conforms well to the lens without causing dark corners when fitted to wide-angle and telephoto lenses. In addition, the filter comes with a high-quality leather storage bag that is purely handmade and specially produced for K&F Concept photographers. K&F Concept's flagship filter meets the highest internal standards and offers excellent optical performance. The classic high-end design and exquisite workmanship make it a valuable addition to any photography equipment. Overall, I would rate the K&F Concept Nano-X PRO Series ND1000 filter five out of five stars. It is of excellent quality and performance and offers excellent value for money.