Virgin TV branded its original high-definition (HD) Digital Video Recorder (PVR) service as "V+". The service uses a PVR set-top box, with three tuners and a 160 GB hard disk for up to 80 hours' recording. The presence of three tuners means that V+ can record two channels at the same time while viewers watch a third. This contrasts with most other PVR systems such as Sky+, which supports only two tuners. In December 2010 a 1 TB TiVo HD PVR from Cisco was released, with a 500 GB model released in May 2011. From late 2011, Samsung Electronics will join Cisco as a second supplier of TiVo STBs for Virgin Media.