Color Graduated filters are used to paint a portion of the scene, often a sky, without affecting other parts of the scene.
Schneider Optics Storm Blue is a rich aqua blue color that is available in both solid and graduated versions. Storm Blue filters can be used to create cool or even cold feeling images. They can also be used to enhance blue of sky and water. Note that the filter color MIXES with the sky or water color to create the final color.