The Prank Box is basically a sealed wooden box with an electric bell inside that is activated by a key switch. Once it is turned on, a relay inside the box is latched and it cannot be turned off without knowing the secret trick (spoiler alert: magnets). Quite understandably, a completely sealed box with a ringing bell inside that doesn't seem to stop can quickly become maddening. It is very funny to watch people ponder the implications of the device, reluctantly turn it on, and then stress out when they cannot turn it off.
NOTE: The wooden enclosure is not supplied with the kit. If you would like to make the wooden enclosure shown, follow the link to the Instructable in the kit instructions for how to build the wooden box.