3TB Drives

Why is the Seagate Constellation ES 3TB drive $320 while the rest are half that amount?

http://www.newegg.com/Product/Productcompare.aspx?Submit=ENE&N=100007603%206000
03269%20600083978&IsNodeId=1&bop=And&CompareItemList=14%7C22-148-844%5E22-148-8
44-TS%2C22-136-893%5E22-136-893-TS%2C22-136-874%5E22-136-874-TS%2C22-148-747%5E
22-148-747-TS%2C22-148-901%5E22-148-901-TS

http://goo.gl/yn538