Here's how I made the ChickenGuard automatic door system work with my horizontally opening door. Note: The ChickenGuard company does not recommended it to be used in this type of application, unfortunately I did not know this before ordering it from the manufacturer. Materials: (Lowes 8/2014) 2 Convert 2" Heavy-Duty Wall/Ceiling Mount Pulley, Model # T7550502, $4.58 1 The Hillman Group 14 Gauge Galvanized Steel Wire, Model # 122065, $7.67 1 Empty small water bottle, $0.00 If you like the ChickenGuard's ability to open the coop's door in the morning when it gets light outside and close when it gets dark but your coop has a horizontally opening door, you could do what we did and devise a ballast that will pull the door closed when ChickenGuard starts to close the door. 1. I found a used but clean small water bottle that still had its cap. 2. I found an area adjacent to the door that would allow the bottle unrestricted vertical movement. 3. I installed one of the Wall/Ceiling Mount Pulleys directly over this area making sure that it was in line with the door. 4. I drilled a hole in the bottom of the door just below the top edge of the sliding track. 5. I then tied the Galvanized Steel Wire to the door, fed it through the track and out the end. I used wire instead of cord because it would be more resistant to curious chickens. 6. Using the wire's location as a guide, I mounded the second Wall/Ceiling Mount Pulley so that it guided the wire up and over the first pulley. 7. I then cut the wire to length and tied the end to the water bottle. 8. I finally poured a little water into the bottle and tested the door to make sure that it closed. After trial and error, I found the right amount of water to put into the bottle that would close the door but not put undue strain on the ChickenGuard's motor.