./bin/atlas backup snapshots download --help                                                                                     
You can download a snapshot for an Atlas Flex cluster.
To use this command, you must authenticate with a user account or an API key with the Project Owner role.
Atlas supports this command only for Flex clusters.

Usage:
  atlas backups snapshots download <snapshotId> [flags]

Flags:
      --clusterName string   Name of the cluster. To learn more, see https://dochub.mongodb.org/core/create-cluster-api.
  -h, --help                 help for download
      --out string           Output file name. This value defaults to the Snapshot id.
      --projectId string     Hexadecimal string that identifies the project to use. This option overrides the settings in the configuration file or environment variable.

Global Flags:
  -P, --profile string   Name of the profile to use from your configuration file. To learn about profiles for the Atlas CLI, see https://dochub.mongodb.org/core/atlas-cli-save-connection-settings.

./bin/atlas backup snapshots download 675acf673a6b85483b198fd9 --clusterName ClusterFlex --out ~/Downloads/test.tgz -P prod   

Snapshot '/Users/andrea.angiolillo/Downloads/test.tgz' downloaded.

./bin/atlas backup snapshots download 675acf673a6b85483b198fd9 --clusterName ClusterFlex  -P prod                                      

Snapshot '675acf673a6b85483b198fd9.tgz' downloaded.