SAN DIEGO — Among the safety measures schools are now employing is a device invented by a retired San Diego teacher that was never designed for the use. Rick Morris taught elementary school for three decades before leaving to focus on books to help educators with inventions. In 2005, Morris designed the Lock Blok, an updated version of a device he invented in the 80s. Applied with an adhesive, a rubber tab is affixed to the door and can be pushed out, again acting like a stopper. It was designed to cut down on noisy door slams in class. Morris said after the Columbine shooting, schools started using the Lock Blok for safety. Most class doors have to be locked from the outside. With Morris' invention, teachers could just keep the door locked all day, even with the Lock Blok engaged. In an active shooter situation, the tab is pulled back, while the door shuts and is automatically locked. Security experts tell us during a true emergency, fine motor reflexes becomes tested. If a teacher has to go outside and try to lock the door with a key, it could take precious seconds. Over the years, some 8000 Lock Blok units have been installed by local schools. "My reaction is if this is helping to make a campus more secure, good for you, but don't put all your hope in one device. Security is bigger than that," said Morris. Morris doesn't market Lock Blok as a safety measure because it wasn't designed for protection, but after a November shooting rampage at a Northern California school, he can't forget the call he got from that district's superintendent. "My wife and I teared up on that one ... If it saved one life, then it saves some parents from grieving," said Morris.