Review on CTA USB Cable Lock – Secure Your MacBook Air/Pro with USB Type A Port – Galvanized Steel Protection with Master Key Compatibility (LT-PL) by Wayne Girard

The concept is great but the mechanism is not very well done. You have to press the button on the end of the lock (under the key in the product image) after inserting it into the USB port to lock it and I couldn't hold the button down even though the right side stood up. Inside the lock are small metal pins for encoding keys, and one of the pins broke on the first attempt to turn the key. Also, with no fault of the product, this lock will not work properly if you have a laptop hard shell as close as possible to the USB port. The lock does not fit snugly into the port and will not engage. For example, I have a hard case on my MacBook Pro and I can't use the lock on the right port, but it fits the left port.