This B&H Kit includes the Synology DiskStation DX513 5-Bay Expansion Unit and five 3TB hard drives. The DiskStation network attached storage solution features five hot-swappable hard drive bays capable of holding both 2.5" and 3.5" hard drives. With a plug-and-use design you can be up and running in no time, simply attach this storage solution to another compatible Synology storage solution and insert the five 3TB hard drives included with this kit. After inserting the five 3TB hard drives, you can begin storing and transferring data to the 15TB of storage perfect for saving a large amount of data. Once the storage solution is up and running, each drive bay can be monitored via the integrated LED indicators ensuring each drive is functioning properly.