The cokin a series a255 modular hood is a great tool for creativity gets rid of unwanted reflections strengthens contrasts and acts as a lens shade by pressing on the upper and lower parts of the lens hood it clips onto the filter holder depending on the focal length of the lens it is possible to attach several modular hoods to one another to create a longer lens shade for telephoto lenses the cokin a series a255 modular hood attaches to the outside of filter holder and doesnt imped