Our PE Tubing (low-density polyethylene tubing), or spline, is commonly used to fill the hem pocket of your fabric awning cover. The PE Tubing creates the space needed to allow your fabric to slide into awning rail. It can also used in most retractable awning covers. It will not rot, absorb water, shrink, or unravel. The polyethylene tubing is 1/4-inch (outer diameter) x 1/8-inch (inner diameter) in size and comes in a 1000-foot roll.