This is a 2-bay NAS and as a “+” model was the highest spec version at time of release.
Synology software support is superb and so this is right up to date with the latest version of the Synology diskstation software.
I have run it with a pair of WD 3TB Green HDs mirrored for resiliency. These are working fine, although one shows some historical bad sectors so worth replacing at some point.
£55 delivered for the NAS or…
Synology DS211+ NAS 6TB