A DPO4000 occupies 5 rack units (8.72 in) in a standard 19-inch rack. For comparison, the TDS 3000B occupies 4 rack units (6.95 in) and the TDS 5000B occupies 6 rack units (10.47 in). The TDS 500/600/700 products also occupy 4 rack units (7 inches).