U2F Zero is a USB token that works with any service that supports U2F, like Google services. It can be registered with 15 different services at a time. It works for 2 factor authentication or sometimes even password replacement. No drivers needed. Just plug it in and press a button. It's open source and fully documented so you can build your own or learn why it's secure. Check out the source here: https://github.com/conorpp/u2f-zero. Note that Google Chrome is the only browser supporting U2F currently. Firefox support is limited.

• Two Factor Authentication Token
• Works with Google, Duo, Github, Dropbox, and anything that supports U2F
• Open Source
• Secure Design
• No Drivers

Two Factor Authentication TokenConorCo LLC