Choose a sturdy table or desk leg to tether your laptop to.

The Kensington MicroSaver Alarmed Computer Lock is a 6-foot covered steel cable with a T-bar lock on one end, and an electronic alarm in a plastic housing on the other. It takes a key rather than a numeric combination to unlock it.

Once we liberated the product from its hard plastic packaging, it was a no-brainer to use: Uncoil the cable, turn on the alarm, thread the lock around something sturdy (like the leg of a heavy table or desk), then through the circular opening on the alarm, and mate the T-bar lock to the Kensington lock slot on your laptop. Push in the key and turn it to attach the lock, and then remove the key.

While the lock is only as good as the strength of the device it’s connected to, we had no problems when we attached it to a deceased PowerBook G4. We tugged firmly on the PowerBook and the cable remained affixed, though the alarm remained silent: It only sounds if you press and hold the test button, or if someone tries cut the cable.

We slashed at the steel cable with a pair of long-handled loppers, and the alarm sounded before we could finish the job. There was no way to turn it off aside from smashing it with a hammer, and the experience was highly nerve-wracking—which is exactly how you want a thief to feel when it’s your laptop on the line.