The LaCie 5TB 2big Thunderbolt and Network Drawer is a spare drive and drawer for use with the LaCie 2big Quadra, 2big Dual, 2big Network 1.1, 2big Network 2, and 2big NAS. The spare drive and drawer increases security in the unlikely event of a drive failure. You can immediately and easily hot-swap a failed drive. The capacity of your spare drive must be equal to or higher than the capacity of the drive being replaced. This drive features a storage capacity of 5TB.