The Synology RX418 is an extension unit for your Synology RS818 + and Synology RS818RP + NAS. Through 4 hard drive slots for 2.5 inch or 3.5 inch internal hard drives you expand the storage space to a maximum capacity of 96TB. Connect the expansion unit directly to your rack NAS and it is immediately ready for use without software installation. You manage your expansion unit via the Synology DSM software on your NAS rack. If the drives in the expansion are not in use, they switch off automatically. This means your discs last longer and you save energy.