MaxDigitalData (MD12TGSA25672DVR) 12TB 256MB Cache 7200RPM SATA 6.0Gb/s 3.5" Internal Hard Drive designed for heavy duty 24/7 operation. It is perfect for Surveillance System, CCTV DVR & Desktop computers (PC/MAC). The MaxDigitalData 12TB hard drive provides an enormous 12TB capacity, 256MB Cache and 7200rpm rotation speed to deliver a greater level of power efficiency and quiet operation for energy-conscious, environmentally-friendly computers. 12TB of capacity to store up to 12,000 hours of HD video (depends on CCTV System.)