Edmunds-Adjustable Stretcher Bars. The bars slide up, down and side to side allowing many different size combinations. Select the bars that are equal to or greater than your canvas's longest edge. Bars are interchangeable with each other to allow for any size canvas. They adjust with your canvas and hold it tight. Easy to assemble, adjustable and light weight. This package contains four 20x20 inch routed stretcher bars and hardware for putting them together. Imported.