Another philips channel balance replacement

This looks like either an S380-20 or S385-20, depending on the depth of the bottom nylon shoe. Compare both with your old hardware to see if either matches. Now, your stamp option of 19-9 is from an old rating system we do not use. To know what stamp option to select, obtain the exact weight of the window sash. You can then match that exact weight with one of the weight ranges listed alongside each stamp option on the product page.