Commercial Automatic Door Opener Door Mount
Welcome everyone into your home or business with this handicap door opener that provides easy opening for interior and exterior doors. This door mounted unit is designed to install on the back of a door that opens inwards. Its function is to pull the door open and it always partners with a door closer on the opposite side of the opener which closes the door once the opener times out and the arm withdraws back into the unit. If a wall is present behind the door when it is open to 90 degrees then a minimum clearance of 8 1/2" of clear space is necessary, failing which it will not open fully and may also malfunction.
More information: http://www.universaldesignspecialists.com/commercial-automatic-door-opener-door-mount/