3 Limits of the AS5202T NAS

No PCIe expansion slot The AS5202T lacks a PCIe slot, so you cannot add a 10GbE card, SSD cache, or other internal upgrades.

No external expansion unit support You cannot connect an expansion chassis to add more drive bays, unlike many competing NAS models.

Storage is capped at two internal bays The only storage you will ever have is whatever drives you install in the two built-in bays. There is no way to increase capacity beyond that.