Comprised of 3.5 in. hard drives with 4 and 6 TB capacities to accommodate extended video retention for analysis and reference, WD Purple™ NV meets demands of scalable network video recorder (NVR) surveillance systems utilizing higher hard drive bay counts and greater numbers of attached cameras. AllFrame™ technology, when combined with ATA streaming support, helps reduce video footage loss with cache policy management technology to help improve data flow and playback.