Most people picture a dongle as a USB stick that slightly hangs out. The GPS unit is about the length of the tablet and about two inches thick. Since the GPS dongle uses the charging/docking port it cannot be used while being charged, nor while connected to laptop dock.
If you did not receive an invite, yet, login to Asus VIP services or sign up for an account. You must register your Asus Transformer Prime. The you can click on GPS Extension Kit Apply & Inquire on the left side menu.
The GPS unit will be shipped to you for free.
Although the TF201 is not a professional GPS device, as part of our unwavering commitment to our customers we are offering all customers who purchased a TF201 system a free external GPS extension kit, called a dongle, which may help improve signal reception and optimize the user experience. It does not replace, alter or amend any existing warranties you may have.
The offer will expire on 31th of July, 2012 (PST).