One of the most innovative recent data center models is the modular data center, often deployed in the form of containers that house complete computer infrastructures. One of the best known systems was the Sun Blackbox, which delivered its modular data center with 280 servers in a 20-foot shipping containers to any location worldwide. These data centers may not have been visually pleasing, but Sun claimed at the time that their cost was only 1 percent of the cost of a data center in a traditional building. The Sun Blackbox was also one of the key proponents of a renewed focus on virtualization, this time as a technology to consolidate server resources.