TDK write-once Certified Plus Recordable Compact Discs (CD-R) offer high-density storage and superior audio recording. TDK Certified Plus CD-R discs are high-reliability, high-durability media that incorporate the latest TDK third-generation CD-R technologies, including ISOPURE recording dye technology utilizing a re-tuned MSi (metal-stabilized cyanine) recording material for higher sensitivity, improved Reflex Mirror Tuning reflective layer technology and a double-layer protective system featuring a HardHat protective coating.