SINGLE BULK PACK...WD Purple WD (WD10PURZ)  1TB Surveillance 3.5" Internal Hard Drive - WD Purple Surveillance Hard Drives are engineered for 24/7 reliable operation in HD security systems with up to eight hard drives and up to 32 cameras.

Single Bulk Pack WD AV-GP 320GB 5400RPM 16MB SATA 3GB/S. 3.5" Serial ATA-300. Drive Transfer Rate 300 MBps (external). Internal Data Rate110 MBps. Features Native Command Queuing (NCQ), IntelliSeek, Preemptive Wear Leveling (PWL), SilkStream, IntelliPark, IntelliPower, GreenPower technology.

Single Bulk Pack    WD Purple 2TB Surveillance 3.5" Internal Hard Drive - WD Purple Surveillance Hard Drives are engineered for 24/7 reliable operation in HD security systems with up to eight hard drives and up to 32 cameras.

Single Pack  WD Purple 3TB Surveillance 3.5" Internal Hard Drive - WD Purple Surveillance Hard Drives are engineered for 24/7 reliable operation in HD security systems with up to eight hard drives and up to 32 cameras.

SINGLE BULK PACK..  WD Purple 4TB Surveillance 3.5" Internal Hard Drive - WD Purple Surveillance Hard Drives are engineered for 24/7 reliable operation in HD security systems with up to eight hard drives and up to 32 cameras.

SINGLE BULK PACK... WD Purple 6TB Surveillance 3.5" Internal Hard Drive - WD Purple Surveillance Hard Drives are engineered for 24/7 reliable operation in HD security systems with up to eight hard drives and up to 32 cameras.

SINGLE PACK... WD Purple Surveillance Hard Drive, 6 Gb/s 128 MB Cache, 5400 RPM

SATA 6 Gb/s. 10TB. 3.5" 210 MB/s; 256 MB Cache. 5400-RPM. WD Purple? surveillance storage is built to handle up to 64 cameras per drive and is designed for 24/7, always on, high-definition surveillance security systems with more than eight bays. SINGLE PACK