WD RE SAS 4 TB Enterprise Hard Drive: 3.5 Inch, 7200 RPM, SAS, 32 MB Cache - WD4001FYYG Industry's highest capacity nearline drive - WD RE SAS hard drives are available in capacities ranging from 1 TB to 4 TB to suit even the most demanding storage needs Highest performance for business-critical applications - WD RE delivers 6 Gb/s transfer rates, sustained sequential data rates of 182 MB/s and high random I/O rates Designed for quality and reliability - With a field-tested 1.4 million hour MTBF, this high performance drive delivers the highest level of reliability for 24x7 operation in up to 100% duty cycle applications Dual port, full duplex connectivity - Offers higher reliability, performance and data availability by eliminating single points of failure, designed for leading business-critical Enterprise topologies Full internal input/output error detection and correction code data integrity protection means the drive finds and corrects potential errors before they ever surface