Source - Electronic House"Electronic House" said:DirecTV's HR20-300 is a 300-GB HD-DVR that's capable of receiving and storing the latest MPEG-4 high-definition satellite broadcasts available in the United States. The HR20-300 works in conjunction with four dedicated DirecTV KaKu band High-Definition Satellites that will deliver up to 150 HD channels nationwide during 2007. The compression technology used by MPEG-4 also allows DirecTV to deliver up to 1,500 local HD channels...
And I think they are calling it the HR20-300 because of the 300 GB HDD inside.