The 4TB Red Plus 5400 rpm SATA III 3.5" Internal NAS HDD from WD is built to handle the workloads of RAID-optimized NAS systems with up to 8 drive bays, including home offices and power users, small to medium businesses, and consumer and commercial NAS systems. This 4TB drive operates using a SATA III 6 Gb/s interface, a 256MB cache, and a rotational speed of 5400 rpm, which all help to ensure uninterrupted data transfers with a rate of up to 180 MB/s. This drive also features high levels of reliability, with 600,000 load/unload cycles, < 1 in 1014 non-recoverable read errors per bits read, a workload rate of 180TB per year, dual-plane balance control technology, and a 1 million hours MTBF. WD's NASware helps increase system compatibility, allowing Red Pro drives to be more easily integrated with your existing network infrastructure, while noise and vibration protection is provided by Rotation Vibration (RV) sensors.