These inflatable tubes are for customers who already have a Sunflex Awning and want to add tubes. Some of you have been asking for a few extra tubes for better performance. These are tubes only, so you will need to add Velcro on your front perimeter tube where you want your extra tube to meet. At the rear against the trailer people have been utilizing various things. It pushes hard enough that nothing it really necessary. However, some people use a piece of rubber that doesn't easily slide and is good against the trailer.