SINGLE BULK PACK WD Red Pro (WD121KFBX) 3.5" NAS hard drives are recommended for use in medium to large NAS systems with up to 24 bays. For systems that use 1-8 bays, please consider WD Red hard drives. Designed specifically with SMB customers in mind, WD Red Pro drives are available for up to 24 bay medium to large NAS environments. Engineered to handle increased workloads from your business, WD Red Pro drives are extensively tested and carry a long 5-year limited warranty. Increase the efficiency and productivity of your business with WD Red Pro drives available for up to 24 bay NAS systems. WD Red Pro drives come equipped with NASware 3.0 technology which increases system compatibility allowing for seamless integration with your existing network infrastructure. Add value to your business by enabling your employees to quickly share their files and back-up folders reliably with WD Red Pro NAS hard drives in your NAS solution. Our exclusive advanced firmware technology, NASware 3.0, enables seamless integration, robust data protection and optimal performance for NAS systems operating under heavy demand. Desktop drives aren't purpose-built for NAS. But WD Red Pro drives with NASware 3.0 technology are purpose-built for NAS. Our exclusive technology takes the guesswork out of selecting a drive and balances performance and reliability in NAS and RAID environments. Simply put, a WD Red Pro drive is one of the most compatible drives available for medium to large NAS enclosures. But don't take our word for it. WD Red Pro drives are a reflection of an extensive NAS partner technology engagement and compatibility-testing resulting in a leading compatibility list for NAS systems. WD Red Pro drives are equipped with a multi-axis shock sensor that automatically detects subtle shock events and dynamic fly height technology which adjusts each read-write function to compensate and protect the data. This combination of technology further protects the drives in larger 1 to 24 bay NAS environments and helps increase hard drive reliability. Our enhanced dual-plane balance control technology significantly improves the overall drive performance and reliability. Hard drives that are not properly balanced may cause excessive vibration and noise in a multi-drive system, reduce the hard drive life span, and degrade the performance over time. Built specifically for RAID and NAS environments, WD Red Pro drives come equipped with error recovery controls as part of NASware 3.0 technology to help reduce drive fallout in RAID applications. A NAS environment that has up to 24 bays is very demanding on a hard drive with added vibration, heat and other factors. This is why every WD Red Pro drive is shipped with extended thermal cycle burn-in testing to help ensure each drive is tested for extended reliable operation. MASTER PACK