Sky, or Sky Plus, is a personal video recorder (PVR) service for Sky Digital. Launched in September 2001, Sky+ allows the user to record, pause and instantly rewind live TV. The system performs these functions using an internal hard drive inside the Sky+ set top box. Its chief competitors in the UK market are the developing non-subscription PVR market, including Freeview Playback, and Virgin Media's V+, which has 3 tuners and a 160 GB hard drive. Sky reported in February 2008 that over 3 million households now have a Sky+ box.