(Muscatine, IA) -- A group of school workers in Muscatine, Iowa have come up with a way to help keep kids and teachers stay safe in the event of a school shooting. They've created a safety device called "The Sleeve." It slips right over the closing arm of a classroom door from the inside of the room. It can withstand 550-foot-pounds of pressure so no matter how hard someone tries to get force the door open, odds are they won't be able to. It was unveiled at Muscatine Community College yesterday and so far, schools from all across the country are expressing interest.