Powerful and scalable 4-bay NAS for growing businesses, 4 x Drive bays for 3.5" SATA HDD/2.5" SATA HDD/SSD, 2 x M.2 NVMe 2280 SSD slots, AMD Ryzen R1600, 4GB DDR4 (upgradeable to 32GB - 2x 16GB), 2 x USB 3.2, 2 x 2.5 Gigabit Ethernet. Compatible RAM Model - D4ES04-4G (DDR4 ECC SODIMM) Expansion Unit Available - DX525 (5 Additional Bays) via USB-C REQUIRES SYNOLOGY DRIVES UNLESS MIGRATING FROM OLD UNIT HAT3300-4T HAT3300-6T HAT3310-8T HAT3310-12T HAT3310-16T