Concern over school shootings recently led a middle school teacher in Iowa to take definitive action, inventing a new device that helps educators protect students and faculty, alike.

Called “The Sleeve,” the product is a 12-gauge carbon steel case that can handle 550-foot pounds of force. Placed on a door’s closer arm, it prevents intruders from entering classrooms, WQAD-TV reported.

Daniel Nietzel, an educator at West Middle School in Muscatine, Iowa, got the idea for the device from an active shooter training held in his district.

Image source: Fighting Chance Solutions

Image source: Fighting Chance Solutions

After hearing the recommendation that teachers tie a belt or a cord around their door’s closer arm, Nietzel realized these elements might not be strong enough to keep intruders out.

So, he and his colleagues formed the company Fighting Chance Solutions and began designing and testing a viable device.

After 10 months of brainstorming and development, The Sleeve was born and brought to market.

“We look at it as a cheap insurance policy,” Nietzel told WQAD-TV. “If you have someone out in the hallway, and you have an active situation, a dangerous situation unfolding and [don't] want to go out into the hallway and lock your door, we want to provide you with a way to close that door.”

According to the product’s website, The Sleeve can be quickly applied and removed and it does not require a key or any installation element that would make it cumbersome to use in the event of an emergency.

“The team of educators understand the pressing need for schools and businesses to be able to lock a door from inside the classroom or office quickly and safely,” reads an official description.

It continues, “They also understand that making any modifications to a door, (which in many cases may be ‘rated’ as a fire barrier), would not only be costly, but may violate state and/or federal fire codes.”

Here’s a video that shows how it works:

The Sleve costs $65 for individual units, though schools can also order in bulk.

(H/T: WQAD-TV)