It might look like a humble Blu-Ray Disc, but this disc is the only storage medium certified by the Pentagon. The M Disc is designed to endure indefinitely, keeping your music safe for the future. Consumer-grade recordable optical discs have been known to fail within a couple of years. this is because a normal disc is recorded by using a laser to score a layer of organic dye beneath the disc's hard outer layer, and this dye is susceptible to breakdown and oxidization over time, a phenomenon known as 'laser-rot.' M-Discs differ in that they use a single inorganic data layer that is physically pitted with a high-powered laser, not unlike a vinyl record. The resulting discs have a theoretical lifespan of over a millennia.