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Please do not drop it in a desk and leave it there or leave it laying about. Please treat it like your keys, or a wallet as, if lost, it can become a problem and will take some time to restore. These devices have a battery, and as such have a 3-5 year expected lifetime.
When you are challenged to provide a Time-based One-Time Password when you are signing in, hit the button on the device to generate a code and input that code within the allotted time to confirm your sign in.
This acknowledgment may change as required.