Tape Gateway, a member of the AWS Storage Gateway service family, adds capability to move your virtual tapes archived in Amazon S3 Glacier to Amazon S3 Glacier Deep Archive storage class, enabling you to further reduce the monthly cost to store long-term data in the cloud by up to 75%. S3 Glacier Deep Archive is a new S3 storage class that provides secure, durable object storage for long-term data retention and digital preservation.  

from Recent Announcements https://aws.amazon.com/about-aws/whats-new/2019/05/aws-storage-gateway-service-adds-capability-move-virtual-tapes-from-amazon-s3-glacier-to-amazon-s3-glacier-deep-archive/