IBM today rolled out a data migration appliance that allows enterprises to move data from their on-premises servers to IBM Cloud via overnight mail.

It’s a suitcase-sized device on wheels that can store 120 terabytes of data.

Like similar mass migration tools from Amazon Web Services (AWS) and Google, users copy their data to the portable storage box and ship it to IBM, where the data is offloaded to IBM Cloud Object Storage. Companies can then use the data across the IBM Cloud platform.

Mailing data to the cloud “seems retro,” said Michael Fork, distinguished engineer and director, cloud infrastructure, IBM Watson and Cloud Platform. “But in a lot of cases it’s the only option to move large amounts of data to the cloud.”

Transferring large data sets can take months, depending on a company’s access to high-speed bandwidth. Enterprises face other data transport challenges including high network costs, limited Internet connectivity, and security concerns, Fork added.

“Our goal is to build the simplest, most affordable way to move large amounts of data to the cloud,” he said.

The device, called Mass Data Migration, includes AES 256-bit encryption to ensure data is protected during transport and ingestion. It also uses RAID-6, which protects against two disk failures. “While these are rugged, tamper-proof, and shock-proof cases, we wanted to make sure that even in the event of a drive failure, we can still read your data and complete a successful migration,” Fork said.

The service is available now in the U.S. IBM expects to offer it in Europe before the end of the year, Fork said.

Some customers have already used the migration tool in beta. “With the recent VMware announcement, we have been migrating a lot of VMware customers to the IBM Cloud,” Fork said. IBM last week announced a new hybrid cloud service with Vodafone that allows enterprises to move their VMware workloads between Vodafone-hosted private clouds and IBM’s cloud.

Another use case comes from companies that need to store, manage, and access large video, audio, and image files.

“Once they get their data into the IBM Cloud, they can leverage cognitive services like Watson Content Enrichment to gain intelligence from their unstructured data and make more informed business decisions about the content they create, acquire, and deliver to users or viewers, Fork wrote in a blog post.

The device and service costs $395, which includes UPS Next Day Air shipping.