Synology eSATA Expansion Unit - Model DX510

The Synology DX510 is a 5-bay NAS expansion unit with support for up to five 3.5" or 2.5" SATA hard drives, a maximum capacity of 10TB (using 2TB drives), and hot-swappable drive support. It connects to a compatible Synology DiskStation via a single eSATA cable and is managed through the Synology DSM software.
 
Supplied with mains cable and eSATA cable. No drives included.
 
Specs
Internal Drives: 5 x 3.5" or 2.5" SATA II drives
Max Internal Capacity: 10TB (with 5 x 2TB drives)
Hot-swappable: Yes
External Interface: 1 x eSATA port
Dimensions:
157mm×248mm×233mm
Weight:
4.10kg
System Fan: 2 x (80mm x 80mm) 
Power 
AC Input:
100V to 240V
Power Frequency:
50/60Hz
Power Consumption:
59W (Access)
18W (HDD Hibernation)
Power Recovery: Synchronised with the Synology DiskStation