The Toshiba MG08 hard drive uses a 9-disk helium design and comes with a 2.5 million-hour MTTF and a 550 TB per year workload rating. In addition to the increased capacity and data density, the 16 TB storage capacity also comes with improved power efficiency over the existing widely adopted 12 TB drives.
https://www.notebookcheck.net/Toshiba-unveils-a-16-TB-hard-drive-the-industry-s-largest-so-far.392976.0.html