To specify the target device of the iOS application.
Universal |
Specify both iPhone & iPad as target device. This is the default value. |
iPad |
Only iPad. |
iPhone |
Only iPhone. |
This property indicates wich device your application was made for.
For example, if you have done the design for iPad, but not for iPhone, you will have to set the property on iPad value, then, your application will be available just for iPad.
In the AppStore you will see the application on the correct category:

In iTunes:

However, it is possible to install an iPhone application on an iPad, but you will see something like this:

Objects Smart Devices Main Objects (iOS)
Native Mobile Main object properties