WD Purple 4TB Surveillance Hard Disk Drive - 5400 RPM Class SATA 6 Gb/s 64MB Cache 3.5 Inch - WD40PURZ

Engineered specifically for surveillance security systems
Supports up to 180 TB/yr. workload rate
Tuned for write-intensive, low bit-rate, high stream-count applications typical to most surveillance applications
Prioritized write-operations for maximized surveillance performance
TLER & ATA streaming support