QNAP 4 bay TS453 U-RP/BU upto 128TB of storage capacity per unit - 8 units NAS

TS453- BU 3. Expand the total raw storage capacity up to 128 TB with the economical UX-1200U-RP QNAP expansion enclosure. PCIe slot supports installing a QNAP QM2 dual-port M.2 SSD/10GbE card, a compatible wireless adapter, or a USB 3.2 Gen 2 card.

eBay