Google Chrome has a very useful built-in feature, specially for the developers. This feature lets you change browser’s User-Agent easily, without installing any extension or using any geeky hack.
You will be surprised to know that the Chrome has built-in feature to modify user agent. It also provides some pre-set user agents, like that of Internet Explorer 9 and Android 2.3. You can specify your own custom user agent to browse internet easily.

To change the user agent in Google Chrome, press Ctrl + Shift + I to launch Developer Tools panel. You can find a Settings button in the bottom-right area of this panel. Just click on this button, which will open an overlay to set various browser settings including user agent as shown on the above screenshot.
Moreover, You can enter custom user agents manually. For example, the user agent of Amazon’s Kindle Fire is given below:
Mozilla/5.0 (Linux; U; Android 2.3.4; en-us; Kindle Fire Build/GINGERBREAD) AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1
Try the above user agent string to see the magic of user agents.
Thanks François, for the tip!