Beginning March 16th, the MacID iOS app is free, but only for 48 hours. It's normally $4. It's an app for your Touch ID-based iOS device, and it works in conjunction with a second app that you install on your Mac. MacID lets you lock your Mac with a swipe of the finger on your Touch ID-equipped iPhone or iPad.

The developer is reducing the price temporarily to celebrate the release of MacID 1.1, which includes the following improvements:

Mac audio controls that work with iTunes and Spotify Clipboard sharing between iOS and OS X Proximity waking An iOS Notification Center widget Auto-lock notifications and sensitivity options Full split-screen iPad support

Don't forget to visit the MacID Web site after downloading the app to install the companion app on your Mac. The Mac app is properly signed to avoid security issues with OS X's Gatekeeper security, provided you've configured your Mac to "Allow Mac to download apps from Mac App Store and identified developers."

Free - Download now