Adam works as a Security Analyst for Umbrella Inc.

Adam works as a Security Analyst for Umbrella Inc. CEO of the company ordered him to implement two-factor authentication for the employees to access their networks. He has told him that he would like to use some type of hardware device in tandem with a security or identifying pin number. Adam decides to implement smart cards but they are not cost effective.

Which of the following types of hardware devices will Adam use to implement two-factor authentication?