Cirago USB 2.0 2 TB External Hard Drive (CST4200-R) Aluminum case for sufficient cooling performance Support Window 8/Vista/2000/XP, Mac OS8.6 or above. For Mac compatibility this Hard Drive requires reformatting. Refer to Application Guide for guidance on this 3.5 inches form factor 12V 1.5A, AC/DC adapter included Plug and play 2 TB External Hard Drive Recertified