Prime-Line Products H 3577 Wood Window Sash Balance, 4.5-Pound 4-1/2 pound counter balance per cable All steel construction coil spring retraction Two steel cables, one for upper sash and one for lower Use either one or two balances per window, 2 each #4-1/2 balances for a 9 pound sash For replacement of existing balance or to retrofit old style pulley and weight