Installing your lens cap is faster and easier than ever. Attach the adhesive metal ring to the outside of the lens filter thread and attach the lens cap to the metal ring. Less time fumbling with equipment, and more time taking great shots. Seamless Shooting, Maximum Protection: Rotate counterclockwise rapidly and the built-in blade automatically opens to capture the breathtaking moment without removing the cap. No more worrying about missing a chance or missing a lens cap. Conversely, gently rotate clockwise to close the blade firmly and instantly protect it from dust, moisture, and nasty scratches.