It's not what project you have in mind that may use a rocket launch switch… The question is what project will you come up with once you have one in hand? Everyone has a proverbial missile to launch.
The hot red safety cover protects a toggle switch from accidentally being turned on. When flipped up, the user has full access to a switch underneath. Upon closing the cover, the cover will force the switch arm back into the lower position - a safety mechanism so you can quickly hit the cover down and deactivate the switch.
Note: This is the cover for the switch only. A compatible toggle switch.