If you already have Cisco STB's, your DVR has a 500GB internal drive. The one time $39.99 fee is to upgrade a non-500GB DVR - which you've already got....
If you want to purchase an eSATA drive, they are available from multiple retailers.
Verizon partners with Western Digital for 2 'approved' eSATA drives, 1 is 500GB and the other is 1TB.
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