While there’s not a whole lot to say about this little app, there’s enough. Rotation locker is a simple little application which provides a method of locking the rotation on your phone. Users with a custom ROM can usually use the built in rotation toggle to have similar effects; with many not being so lucky, this application makes locking it a simple task.
When launched, the application simply opens a pop-up dialog which gives you the option of Portrait, Landscape, and Auto (to return it to normal). Many users which want a quicker way to access the rotation settings via the app or widget will find this useful; other users simply do not have auto rotate simply because the sensor is broken due to a custom ROM can still use this application to manually set both portrait and landscape allowing to still have full use of your phone.
If you’re a tweaker and would like certain applications to launch with a specific orientation you can combine this app with Tasker to create a profile on a per-app basis. If you find a thread on XDA where people are unable to use sensors, make sure to point them towards this app. The small but incredibly useful application is available for free on the Play Store.