Non-volatile data memory cards, flash drives and other memory devices are customized by manufacturing core memory units all the same and then covering them by outer skins which may be made to have different appearances and/or tactile characteristics. The skins are slid over the core memory units by hand from one end. End users of such memory devices may then select how they will look and feel by separately purchasing covers. Sellers of such memory devices may more easily control how their products look and feel.