WD SE Enterprise 4TB SATA3.0

Designed for quality and reliability. All drives undergo at least 5 million hours of functional testing, and over 20 million hours of additional testing under actual workloads in actual server and storage systems.
StableTrac. The motor shaft is secured at both ends to reduce system-induced vibration and stabilize platters for accurate tracking during read and write operations
Thermal extended burn-in test. Each drive is put through extended burn-in testing with thermal cycling to ensure reliable operation.
Dual processor. Twice the processing power to maximize performance.
Multi-axis shock sensor. Automatically detects the subtlest shock events and compensates to protect the data.
Dynamic fly height technology. Each read-write head’s fly height is adjusted in real time for optimum reliability.