M-DISC 4.7GB DVD+R Permanent Data Archival / Backup Blank Disc Media - 50 Pack Archival Grade-able to store digital content without data loss for decades up to 1,000 years. Tested-The Naval Air Warfare Center at China Lake declared the M-DISC as top rated after testing the M-DISC against the best conventional archival discs on the market. Long Lasting-utilizes chemically stable and heat-resistant materials not used in any other DVD or optical disc for greater longevity. Stability-cannot be overwritten, erased, or corrupted by natural processes unlike competing archival media. Durable-resistant to damage caused to typical optical media from extreme temperatures, humidity and sunlight.