WD Purple 4TB 1TB 2TB 3TB 6T Surveillance Internal Hard Drive Disk 3.5" 64MCache SATA III 6Gb/s HDD HD Harddisk for CCTV DVR NVR. HDD Capacity ：1TB/2TB/3TB/4TB/6TB. 4TB = about 3724GB. 3TB = about 2793GB.
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