 "WD Purple WD10PURX 1TB Surveillance 3.5" Internal SATA Hard Drive"
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                Overview:
The 1TB 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 1TB 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
1 TB capacity holds up to 200,000 digital photos, 250,000 MP3 files, and 120 hours of HD video.

Specifications:

1TB Storage Capacity
3.5 Form Factor
6 Gb/s Data Transfer Rate
64MB Cache
Surveillance Class Storage
Supports up to 32HD Surveillance Cameras

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 "WD Purple WD10PURX - Surveillance hard drive 1TB" " WD 1TB Internal Desktop Hard Drives CDWG.com
"WD Purple Surveillance Storage offers exclusive AllFrame technology to bring you premium reliability and peace-of-mind when installing your home or small to medium business security system. WD Purple's exclusive firmware upgrades work with ATA streaming to reduce error pixilation and video interruptions that occur when desktop hard drives are incorrectly used as storage in security systems. WD Purple Surveillance Storage is built for 24/7, always-on, high-definition surveillance security systems that use up to eight hard drives and up to 32 cameras.You wouldn't use a bicycle to transport cargo across the country because it's not the right tool for the job. You also shouldn't use a desktop hard drive in your surveillance security system because it wasn't designed for that application. WD Purple surveillance-class storage has been tested to be compatible in a wide-range of security systems. These drives are designed to replace standard desktop drives that were not designed for the harsh 24/7 always-on, high-definition surveillance environment. Desktop drives are built to run for only short intervals and are not engineered to withstand high-temperature fluctuations and equipment vibrations found in a typical surveillance application." 