The Battery Powered Door-Propped Alarm EAX-300 from Detex Corporation of New Braunfels, Texas, sounds an alert when a secure door is propped open. The low-cost solution requires no electrical connection and is easy to install. The battery-powered alarm can be field-set for door-open times ranging from one second to two minutes, with a 15-second default. The 100-decibel alarm alerts employees, and silences when the door is closed so there is no waiting for a key to arrive. Weatherized models are available for exterior doors.