Summary: I have a Synology DS213+, Upgraded from an original ReadyNAS. I underestimated the storage I would need and with just the DS213+ so I purchased the 2Bay Expansion Unit. For hard drives used the WD Red 3TB, which are also in the DS213+. Hook up was easy for power and link cable to the main unit.
Summary: I love all of their products. This allowed me to easily expand a client's DS710+ that had 2x4TB to 4x4TB of storage. Just plugged into the DS710+ with the provided custom eSATA cable and you are good to go. The custom eSATA cable contains thumbscrews that hold the cable SOLIDLY in place.
Summary: This expansion unit is not supposed to work with my DS212+ Synology unit according to their web site. Of course, it does. Set the rear switch to have it power up with the NAS as well as power down at the same time. Great convenience. Or leave it powered off when not needed.
Summary: I am very impressed with this network drive. It has exceeded my expectations and left me completely satisfied. I've had it for a couple of months now and no issues whatsoever. It was easy to set up and is a quality piece.
Summary: I have this connected to my 214DSplay, and it works fine. I have 2 4TB WD Red Drives in each unit, and I use the entire 8TB on the main unit, and I back up that data on Volume 2 on this one which is configured in the Synology Hybrid style of things.
Summary: Bought this for back up for my DS214+. It was easy to set up and can be an additional RAID volume or 2 additional single disk volumes. I'm not sure why some are complaining about the plastic housing.