How to make a bootable Kali Linux 2.0 USB.
Some of the reasons for using a Live USB are : You use all of your system resources (CPU, RAM, GPU, etc) · You take no space of your Hard Drive for it. You can take your OS to any PC you use. And you just need a USB flash drive of at least 4 GB with nothing on it to get it, so why not give it a try?
All you'll need a program to install Kali on your USB drive and make it bootable. My program of choice is Universal USB Installer, as it's painfully easy to use and it has a direct link to many Linux distros download page within the program.