Feel free to file this under "why the <insert favourite obscene word> would I need to know this?" or 'unbelievably pointless', but should you so happen to own a fighter jet and are able to take off from your driveway you will at least have some peace of mind that your Lumia 800 would survive MACH 5 speeds should it be thrown out of said jet in mid-flight.
NokNok decided to put the toughened Windows Phone to the test with a wind tunnel capable of blasting air at MACH 5. Unfortunately you would need to have a cushion for the handset to land on, or you could be a real 'badass' and swoop down in your fancy jet to catch it before the device ultimately crashes into the Earth.
So, should anyone query your vast knowledge of smartphones for a handset that can withstand MACH 5 speeds and be a unique user experience, you'll know which direction to point them in.