Glynn Johnson Sensaguard 280 – Is it right for your application? The Glynn Johnson Sensaguard 280 is the correct overhead door holder for you if you have an existing door closer and your Fire Marshall or Building Inspector has asked you to keep interior doors closed. Generally, many apartment buildings have doors that the tenets prop open with door stops or wedges. The Fire Marshall or Building Inspectors want these doors closed to contain a fire, if there is one. Most of todays modern buildings have door closers wired into there fire alarm, if the fire alarm goes off, the doors close. The Glynn Johnson Sensaguard 280 has a built in smoke detector, when it senses smoke, it automatically closes the door. The door holder is powered by a household 9 volt battery, that automatically releases the door when the voltage drops below 7.2 volts. The Glynn Johnson Sensaguard 280 comes in powder coated aluminum color or dark bronze (dark brown).