The  Dual-Port 10 Gigabit SFP+ PCIe 3.0 x8 Ethernet Adapter  from  Synology  provides two 10GbE ports for select Synology FS/XS+ series NAS servers.

This adapter is installed inside your server’s PCIe 3.0 x8 slot to provide transfer rates of up to 10 Gb/s for networking connections. Included along with the adapter are low-profile and full-height brackets, which help ensure compatibility with your NAS server. Additionally, the two ports have link-aggregation support.