You are getting Tails 3.10.1, Kali 2018 and Ubuntu 18.04 on 16GB USB
Every edition can work stright from the USB. You can test all of them and then choose which one you want to install.
The Linux that you will be getting are:
Ubuntu Desktop LTS is the world's favourite Linux operating system, with more than 20 million people users.
It arrive packed with many software such as Web browsing Firefox already installed, LibreOffice which is a fully-featured replacement for Microsoft Office.
Tails is a live operating system built on Debian that uses Tor for all its internet traffic. Its main goal is to give you security through anonymity. With it, you can browse the web anonymously through encrypted connections.
All your traffic is routed through Tor to hide your physical location or see which sites you visit.
Kali is built on Debian and maintained by Offensive Security Ltd.
With around 300 tools for testing the security of a network, Kali's main focus is on pen testing, which means it's great for poking around for security holds in your own network.