What are Eyelash Extensions? Locks Lash extensions are beautifully crafted eyelash extensions made from the highest quality materials. Our lashes are independently tested to ensure their quality. One eyelash extension is bonded with a premium eyelash extension adhesive to one of your own natural lashes. This attachment is repeated right across your lash line until you are left with a totally natural enhancement of gorgeous lashes. Locks Lash extensions will add length, dramatic colour, and density to your own lash line. These lashes can last from 4-6 weeks. No mascara is needed, and the health of your own lashes will not be damaged.