When navigating a large or small ship, complete clear visibility is essential.  If the Sun is very bright, and glare is coming off the water, it is possible not to see a small vessel or other object in front of your vessel.  Mylar Sun Screen Shades are retractable, and allow for clear sharp visibility when the Sun is bright and the glare is in your eyes.  When not needed, just roll them up out of the way.  The shades will also allow for better view of your instruments.  Safety is our goal, lives may depend on it!