The Lacis Backstrap Horsebar is a self-locking bar that holds your finished weaving section without causing distortion. It locks your work efficiently while letting you make adjustments easily. Use this backstrap horsebar for all your backstrap weaving techniques including card weaving, belt weaving and more. This tool works with belts up to 4.5 inches in finished width. The pack includes a 5-inch backstrap horsebar with helpful instructions.