ImageUSB is a free utility which lets you write an image concurrently to multiple USB Flash Drives. Capable of creating exact bit-level copies of USB Flash Drive (UFDs), ImageUSB is an extremely effective tool for the mass duplication of UFDs. ImageUSB also supports writing of an ISO file byte by byte directly to an USB drive (*). ImageUSB can also be used to install OSFClone to a USB Drive for use with PassMark OSForensics™.
With ImageUSB from PassMark Software, you can easily create exact image copies of any USB flash drives and store them on your PC.
Plug in the USB drive you want to back up and click on ‘Refresh Drives’. You should see your USB flash drive, referred to as a UFD by the program, at the top of the application window. Select it and then ‘Create from UFD’ below. For security, you can also select Post Image Verification to ensure that your backup matches the original UFD. This will create an image file of your UFD with the extension .bin.
You can now copy this image on to another UFD, or multiple UFDs simultaneously by selecting them all before clicking the Write to UFD button. In our example, we have plugged in four UFDs at the same time for duplication.
Unlike other USB duplication tools, ImageUSB can preserve all unused and slack space during the cloning process, including the Master Boot Record (MBR). ImageUSB can perform flawless mass duplications of all UFD images, including bootable UFDs.
DOWNLOAD:
http://www.osforensics.com/tools/write-usb-images.html
For usage you can read following article:
http://www.pcadvisor.co.uk/how-to/storage/3509099/create-image-backup-of-usb-drive/