To use these replacement lenses, first, carefully remove the old lenses from your Demos eyewear. Then, align the new Koo lenses properly and gently insert them into place. Make sure they fit snugly. When wearing, these lenses will provide great visual clarity according to the light conditions. For example, the photochromic lenses will adjust automatically. Keep in mind that avoid scratching the lenses with sharp objects. When cleaning, use a soft microfiber cloth and a mild lens cleaner. Wipe the lenses gently in a circular motion. Store the lenses in a protective case when not in use to prevent damage.