Seagate 4 TB Terascale HDD SATA 6Gb/s 64MB Cache 3.5-Inch Internal Bare Drive (ST4000NC001) Affordable storage for 24x7 multi-drive replicated environments High vibration tolerance for reliable enterprise-class performance Low power and cooling costs with the lowest 3.5-inch enterprise drive operating power Advanced format logical block management for industry-leading data integrity 4TB per drive enables scalable high-capacity storage in 24x7 environments SATA 6Gb/s interface optimizes burst performance