Hard Drives
WD Red Pro 4TB NAS 3.5" Internal Hard Drive - 7200 RPM Class, SATA 6 Gb/s, CMR Recording Technology, 256MB Cache
7200RPM performance class Available in capacities ranging from 2-22TB with support for up to 24 bays Supports up to 300TB/yr workload rate Enhanced reliability with 3D Active Balance Plus technology and error recovery controls with NASware 3.0...
https://www.bizrate.co.uk/harddrives/wd-red-pro-4tb-nas-oid8809190439.html