how to dupplicate exactly an usb pen

[abdelkader belahcene <abelahcene@gmail.com>]

Hi,

I have a bootable usb  containing  on livemint distro, created by unetbootin
I want to dupplicate this pen, in another pen with enough space.
I used
 dd if=/dev/sdc  of=/dev/sdb bs=1M conv=noerror

the new is not bootable,  I tried install-mbr , it failed too.
any idea please, or may be use another   tool
thanks