My HBA is an LSI 9207-8e (http://www.lsi.com/products/host-bus-adapters/pages/lsi-sas-...) and my two SAS expander chassis are NORCO DS-24E (http://www.norcotek.com/item_detail.php?categoryid=8&modelno...), which are just cases that include Areca ARC-8026 SAS expanders (http://www.areca.us/products/sascableexpander.htm) built-in.