Clicking 'Portable Firefox' will open Firefox from your portable device, wait a while before Firefox start.Drag the 'Portable Firefox OS X' folder to your portable device, USB thumb drive, iPod, portable hard drive, memory card, other portable device (also to your internal hard disk) as long as it has 57 MB of free space.Portable Firefox is the popular Mozilla Firefox web browser packaged so you can carry around with you on any portable device, USB thumb drive, iPod, portable hard drive, memory card, other portable device (also on your internal hard disk) as long as it has 57 MB of free space and use on any Mac OS X computer, taking your bookmarks, extensions, history, cookies, and saved passwords with you.