1537-N - Western Digital WD Purple 4TB Surveillance Hard Drive Disk, 5400 RPM Class, SATA 6 Gb/s, 64MB Cache, 3.5 Inch (

Overview: The 4TB Purple Surveillance Internal Hard Drive from Western Digital is designed to withstand the stresses placed on it in a 24/7 surveillance system. With support for up to 32 high-definition surveillance cameras this 4TB hard drive can hold a large amount of data and gives you the ability to easily upgrade and expand your security system. Built for always-on surveillance storage applications AllFrame technology for reduced pixilation and video interruption Designed to support up to 32 HD cameras Caching algorithms specifically designed for security surveillance operation 4 TB capacity holds up to 16,000,000 digital photos, 2,000,000 MP3 files, and 960 hours of HD video. Specifications: 4TB Storage Capacity 3.5 Form Factor 6 Gb/s Data Transfer Rate 64MB Cache Surveillance Class Storage Supports up to 32HD Surveillance Cameras