16 BAY HDD BACKPLANE & CAGE SFF UPGRADE DELL POWEREDGE R720 8 BAY SFF SERVER | eBay
Amazon.com: Seagate 2TB 7.2K 3.5" 6Gb/s SAS Hot Swap Hard Drive with Tray Compatible with Dell PowerEdge R710, R720, and R730 Servers (Renewed) : Electronics
300GB 15K SAS 6Gb/s 2.5" HDD for Dell PowerEdge Servers – Water Panther
Dell 22FYP for Dell PowerEdge R720 and R820 Servers
R749K Dell ST3450857SS 450GB 15K 6Gbps 3.5" SAS Hard Drive