Western Digital 320 GB AV-25 SATA 3 Gb/s 5400 32 MB Cache Bulk/OEM AV Hard Drive- WD3200BUDT 24x7 reliability - These drives are designed to last in always-on streaming digital audio/video environments such as DVR/PVR, digital video surveillance and other demanding multimedia applications. Optimized for smooth, continuous digital video playback of up to five simultaneous HD streams. SilkStream is compatible with the ATA streaming command set so AV customers can use standard streaming management and error recovery options. Ultra-cool operation - A cool drives is a more reliable drive. WD continues to develop new and innovative ways to keep drives cool while they are operating. Quiet - Noise levels have been minimized to virtually below the threshold of human hearing. Low power consumption - The drive draws less than 2 Watts while operating and a mere 4.75 Watts during spin up. 3 year limited warranty