This is a 6TB (Terabyte) Hard Disk Drive. It is the highest quality hard drive you can buy for security NVRs and DVRs. In fact, in order to ensure your security recorder is recording above industry standards, a hard drive such as this is necessary. These are not desktop computer hard drives. Computer hard drives cannot take the high temperatures and constant recording that DVRs and NVRs need to record to. These Security Hard Drives are specifically manufactured to handle 24/7 recording for long periods of time.