The coupler is exactly what you need when you want to join two or more Atlas XL panels together to create a run that is longer than 8 feet. Let's say you have a 10-ft section in your living room and you order 2 x 5-ft sections plus a coupler. That's it and you are done! Just don't forget your end caps! Dimensions: 2.75-in (W) x 3-in (D) x 9-in (H).