This non-tilt block and tackle channel balance is constructed of a mill-finished steel U-frame housing. The internal working components include a spring, cord and pulley system, but the plastic top and bottom guide shoes must be selected separately as they are not included with the balance itself. These window counter balances are used to counter-weight the moving sash on single and double hung vinyl windows. If your windows (sashes), are having problems staying up when opened, it may be that your sash balances or hardware needs to be replaced. The sash balances hold the weight of the window pane, over time, the springs can wear out or fail. Replace your sash balance for a smoother operation of your window and allow fresh air to enter your home with a window that stays open. The information below is per-pack only Can be used on most single or double hung windows Heat treated high tension steel spring Will offset the weight of a window between 15 and 18 pounds 5/8 inch aluminum channel housing Compare old guide ends and note their dimensions to order the new guide ends Size 9/16 in. (Pack of 2) Color Mill Item Weight 15.5 ounces Part Number FA 2330 Manufacturer Prime-Line Products Item model number FA 2330 Batteries Required No Product Dimensions 25.75 x 2 x 0.63 inches Item Package Quantity 1