I think it is cheapest at the moment.
Industry's first 16TB drive
Standard Model FastFormat (512e/4Kn)
Helium sealed-drive design delivers lower total cost of ownership through lower power and weight
Digital environmental sensors to monitor internal drive conditions for optimal operation and performance
Proven enterprise-class reliability backed by a 2.5M-hr MTBF rating
Note: There is also a long running deal $475 (https://www.ozbargain.com.au/node/557264). It is lot cheaper if the drive in the enclosure is same.
Price in title.