This is a nice Ultrastar SS220 and the pictures say Nov 2017 so they're about 19 months old only and they're saying open box. $509 is reasonable for SAS3 with plp.
https://www.ebay.com/itm/HGST-3-84TB-Ultrastar-SS200-SDLL1MLR-038T-CCA1-0TS1404-2-5-SAS-12Gb-s-SSD/223463453402
Right now there's an ES 3.2TB Hitachi drive on auction but the cheapest BIN for 3.2 TB is $649 https://www.ebay.com/itm/SUN-7342260-3-2TB-2-5-SAS-SSD-DISK-DRIVE-342259/173502546973
It's also less than twice the price of the lowest 1.6TB older SAS2 SSD I'm seeing at $320 BIN https://www.ebay.com/itm/HP-1-92Tb-SAS-6-0Gbps-2-5-Inch-Enterprise-SSD-787177-003-HSCP1920S5XNFMRI/254146396633
https://www.ebay.com/itm/HGST-3-84TB-Ultrastar-SS200-SDLL1MLR-038T-CCA1-0TS1404-2-5-SAS-12Gb-s-SSD/223463453402
Right now there's an ES 3.2TB Hitachi drive on auction but the cheapest BIN for 3.2 TB is $649 https://www.ebay.com/itm/SUN-7342260-3-2TB-2-5-SAS-SSD-DISK-DRIVE-342259/173502546973
It's also less than twice the price of the lowest 1.6TB older SAS2 SSD I'm seeing at $320 BIN https://www.ebay.com/itm/HP-1-92Tb-SAS-6-0Gbps-2-5-Inch-Enterprise-SSD-787177-003-HSCP1920S5XNFMRI/254146396633
