Synology DiskStation DS1520+ is an ideal network-attached storage solution, suitable for small office and IT enthusiasts. Two built-in M.2 SSD slots and Synology SSD Cache technology allow you to boost system I/O and application performance. With scalable storage design, DS1520+ lets you start small and expand storage capacity with the Synology DX517 as your data grows.Extended Warranty - Extend warranty from 3 years to 5 Years with the additional purchase of EW201 ( Extended Warranty license must be registered at the same time as the NAS) , Fixed RAM - 8 GB DDR4 non-ECC (4 GB onboard & 4 GB SO-DIMM)