The Mobile Activated Object (aka "MAO") is the most lightweight extension to show and hide page elements according to the device.
It can be configured for mobiles (by default) or even for specific browsers and also supports redirection.
HTML 4.01 Transitional
How to use?
1. Design your page as you usually do.
2. Drag and drop the extension and enter the object names that you need to show or hide on
3. Preview or publish.