Can be used on most single or double hung windows Heat treated high tension steel spring Will offset the weight of a window between 14 and 17 pounds 5/8 inch aluminum channel housing Compare old guide ends and note their dimensions to order the new guide ends Must select the top and bottom guide ends that are sold separately Prime-Line part H 3740 riveting tool can be ordered separately for installation of guide ends Please refer to the line art drawing for dimensions and compare with your needs before ordering