Western Digital RE 4TB 3.5" Serial ATA III

WD RE Enterprise SATA Hard Drives
Ideal for enterprise servers and storage, video surveillance, and other write-intensive applications, WD RE 7200 RPM Enterprise SATA hard drives offer up to 4 TB capacity,
64 MB cache, 4th generation vibration tolerance and 5-year limited warranty.
A head positioning system with two actuators that improves positional accuracy over the data track(s). The primary actuator provides coarse displacement using conventional
electromagnetic actuator principles. The secondary actuator uses piezoelectric
motion to fine tune the head positioning to a higher degree of accuracy.