If you don't have a smartphone, or don't wish to use your personal device, you can choose to use one of two types of hardware tokens, either a Duo FOB or a Yubikey. Both can be attached to your keychain so you always have them with you.
The FOB is a small device that you can attach to your keychain. When you are two-factoring, one of the options is to enter a passcode. You push the green button on the FOB and it will give you a 6-digit number that you can then enter into the passcode box. The passcode changes every 60 seconds and is only good one time. So if you need to two-factor again, you simply press the button again to get a new passcode.
The FOB is hardware independent, so you can use it on any device from which you are trying to log into SUU resources.
The cost of the FOB is $20.
The Yubikey is a USB token that plugs into a computer that has a USB port. When you are two-factoring, you plug the Yubikey into your computer, select the option to enter a passcode, and then push the button on the Yubikey. The Yubikey acts like a keyboard and will type a code into the passcode box. Like the FOB, it is a one-time use code, and changes every 60 seconds. You simply push the button again if you need to two-factor a second time.
The Yubikey is USB based, and thus can only be used on devices that have a USB port.
The cost of the Yubikey is $34.