The Western Digital WD43PURZ 4TB 3.5" Internal SATA/600 hard drive offers an impressive 4TB of data storage capacity, designed to handle a workload of up to 180TB/yr. It also features CMR recording technology and AllFrame technology for smoother, clearer recordings and playback in mainstream surveillance systems. With its 256MB cache size and a transfer rate of up to 175MB/s, you can trust that your data is always safe and secure.