Due to lack of demand, the USB Ignition Key has now been removed from the Reason Studios Shop.
The USB Ignition Key was originally included with Propellerhead Record and Reason 6/6.5 so you could authorize the products for off-line use (without Internet connection).
From Reason 7 and later the USB Ignition Key was replaced by Computer Authorization, so that you could authorize your computer (like a "soft" Ignition Key) for off-line use.