A tubular sleeve is provided for enabling a physician to impart a preselected shape in an implantable tubular device, such as a cardiac lead, a catheter or some other tubular structure. The magnetic disk includes a flexible magnetic recording medium, and at least one rigid ring mounted on the circumferential edge portion of the magnetic recording medium. The olefinic thermoplastic elastomer composition is a composition comprising 1 a specific syndiotactic polypropylene copolymer, and 2 at least one selected from a polypropylene resin and an olefinic thermoplastic elastomer. In some embodiments, the corresponding pattern on the back side is a mirror pattern that matches the functional pattern in size, placement, and number.