Hello Chetan,
The CurrentDevice object holds information about the device detected for the current visitor. The system identifies devices based on their user agent and retrieves the data about the capabilities of devices from the integrated 3rd party component 51degrees.mobi.
Note that most of the properties are only available in the 51degrees.mobi Premium data. By default, Kentico includes the Lite license which you can upgrade. So I'm afraid you will need to but a license for Premium Data if you are willing to use this functionality.
For more details please take a look at the bottom of the following page in the Documentation:
Using 51degrees.mobi device data
Best regards, Martin