HOYA FUSION ONE is a series of filters based on new HOYA optical technology. It is an update on the best-selling HOYA PRO-1D series, which has been widely used by amateur and professional photographers all over the world. The word "ONE" in the naming of this series is maintained as legacy of HOYA PRO-1D, in memory of its contribution to photographers' creativity, with the belief that this new series will serve well for many decades ahead. FUSION ONE filters have been designed to match the rigorous standards and optical capabilities of modern, high-resolution lenses. They join the HOYA filter line-up as a fusion of all the highly valued specifications: Multi-layer coating, ultra-high light-transmission, professional-grade optical glass and a low-profile filter-frame. They additionally incorporate stain resistance and a water-repellent coating. The PROTECTOR filter is designed for constant use and is recommended for shielding your valuable lenses from expensive front element damage that could be caused by knocks, dirt or scratches.