this unit is a used Synology DS423+ 4-Bay NAS Network Attached Storage Enclosure that includes 4 Hard Drives. 

2 used 18TB Western Digital Drives WD181KFGX-68AFPN0
1 used 18TB Dell EMC EXOS X18 STL014
1 used 8TB Seagate Barracuda Compute SKR004

Please refer closely to pictures for EXACT description on each item.  I have described the unit to the best of my knowledge, if you have ANY questions or discrepancy in pictures vs description please send me a message. What you will receive is exactly what has been pictured

LPP