After Sony released the PSP in various revisions, the PSP Go was released in 2009 as the next to last version, following a quite different approach: the housing has totally changed and is much smaller, equipped with a sliding-mechanic. Furthermore, there is no power-consuming UMD-drive anymore. Instead, games are only available for purchase in the PSN store. The PSP Go hat only moderate success and was sold below its suggested retails price in 2010 already, even with 10 free download-games added.