YKK Conceal Invisible Zipper 22" closed end turquoise blue. When the slider on YKK's CONCEAL® zipper is closed, the zipper disappears to look like a finished seam. This zipper is best suited for dresses and skirts since it does not disturb a garment's design. The CONCEAL® open-ended zipper is also recommended for the jackets that require that the zipper's open-parts must be hidden.