Check if your DVR supports external eSATA or USB 3.0 drives—many allow larger, faster, and quieter upgrades without a proprietary module.
If you buy this, buy from a seller that offers a specific return policy for dead-on-arrival (DOA) units. Test it immediately by recording two HD channels simultaneously to stress-test the drive. If it passes the first week, it will likely serve you well for a few years. arris dvr module 500g