WD Purple, The Right Drive for Smart Video Surveillance. WD Purple drives are designed to meet the challenges of 24x7 video surveillance recording. These drives are engineered specifically for surveillance to help withstand the elevated heat fluctuations and equipment vibrations within NVR environments. An average desktop drive is built to run for only short intervals, not the harsh 24/7 always-on environment of a high-definition surveillance system. With WD Purple drives, you get reliable, surveillance-class storage that s tested for compatibility in a wide range of security systems. Exclusive WD AllFrame technology helps reduce frame loss and improve overall video playback *** SINGLE PACK ***