Western Digital says that it has released a new version of its My DVR Expander hard drive, now officially certified for TiVo HD and Series 3 recorders. The Expander is an external device that enables DVRs to record programming over and above their normal limits; the first of the new Expanders is sized at 500GB, which should be enough to hold as much as 300 hours of SD broadcasting, or 60 hours of HD content. The drive remains compatible with Scientific Atlanta 8300 HD, MR and HD-MR DVRs, with certification expected to increase as more DVR makers introduce eSATA functions. The TiVo-ready Expander is being sold at retail and through TiVo's online store for $200.