When the user leaves the preset range, Airlock locks the Mac's screen, and upon the user's return, Airlock automatically unlocks the screen. As a fallback for when the user's iPhone or iPod touch's battery is dead, Airlock can be configured to accept the user's account password to unlock the screen.

Airlock runs in the background and is configured through the System Preferences. From the Airlock preference pane, users can configure many aspects of the app. For example, the Airlock preference pane features a radar screen which allows users to configure the distance that Airlock considers in-range, while displaying the location of the user's iPhone or iPod touch in realtime.

In addition to locking the screen, Airlock can be configured to perform custom actions as the user comes and goes. For example, when the user comes in-range, he or she could automatically be logged-in to iChat, a favorite news site could be refreshed, or a daily snapshot could be taken of the Mac's surroundings. On the other hand, when the user goes out-of-range, he or she could be logged-out of iChat, or an email could be sent logging the time and date that the user left.

Version 1.0.1 -- free to registered users -- is now able to detect certain newer-model iPhones in the iPhone-selection sheet within the Airlock preference pane. The software can also now detect a user's iPhone with no dot appearing on the radar screen, and with the range indicator remaining black.

Airlock requires an Intel Mac running Mac OS 10.5 or higher and an iPhone or iPod touch. It runs solely on a user's Mac (nothing needs to be installed on a user's iPhone or iPod Touch.) A free, full-featured demo of Airlock is available. Registration is US$7.77.