The 1504 Series electromagnetic door holder is a high quality device for use with single doors. The electromagnet assembly is designed for flush wall mounting. The electromagnet is designed to be flush wall mounted inside a standard single gang outlet box. Field wiring connections are made to the electromagnet inside the electrical box. The catch plate assembly may be mounted to the door either by through-bolting or by using the concealed surface mounting plates. Designed to be used on self-closing, swinging doors to automatically isolate an area when activated by fire alarm, smoke detection or sprinkler systems. Can also be operated by manual control; offices (instant privacy by pushing a button on your desk), nursing homes and public buildings. The 1504 Series door holder is an auxiliary device designed for wall mount applications that require holding single doors.