Connect an HD source like a satellite or cable box, HD disc player, PC, or even an Apple TV, and it will stream the content to a SlingCatcher, laptop or desktop computer in your home or connected anywhere via the internet.
Add the optional SlingPlayer for mobile application and you'll also be able to access the content on your mobile phone, and in the near future, tablet devices like the iPad.
As long as your connection is fast enough the picture will retain the original resolution, and if not, the device will scale down the image to ensure you get a smooth performance.
There's an onboard Freeview tuner with aerial pass-through, too, so you can watch TV and change channels from wherever you are without upsetting the people watching at home, but surprisingly the tuner itself isn't HD.
It's also worth pointing out that the Slingbox PRO-HD doesn't have HDMI inputs or outputs, instead relying on component connections for HD, and composite and S-Video for standard-definition.
The company is also launching Slingbox.com, an online web portal that allows you to login and watch your content directly through a web browser, negating the need to download the dedicated SlingPlayer application.