Iomega 320 GB USB 2.0 eGo Helium Portable Hard Drive Perfect match for the new MacBook Air notebook (HFS+ format) The compact silver design slips easily into a purse or briefcase Iomega eGo Helium can withstand the toughest of travel environments Iomega eGo Helium Portable Hard Drive requires no external power supply Available in 320GB capacity,holds up to 1,280,000 photos, 5,920 hours of music, or 480 hours