4 TB hard drive in 3.5 "format with SATA 6 Gb / s interface. Model WD40PURX from the manufacturer Western Digital. Designed and manufactured especially for storage in Video Surveillance systems of up to 32 HD cameras and 8 hard drives. They ensure an optimal functioning permanently during 24 hours, 7 days a week, at high temperatures. This model minimizes the level of noise, vibration and power consumption, extending the life of the disc compared to conventional HDD. On the other hand, it increases the reliability of audio / video storage using AllFrame technology, which allows reducing the loss of images, improving reproduction and increasing the number of compartments supported. The failure rate is considerably reduced thanks to strict functional integrity tests carried out at the factory. The hard disk is distributed loose or installed in any of our video recorders.