Replacement Channel Balance

This looks like either an S380-30 or S385-30, depending on the depth of the bottom nylon shoe. Compare both with your old hardware to see which matches best. Now, your stamp option of 2990 is from an older rating system we do not use. I believe that last pair of digits, the 38, may refer to the exact weight of the window sash. If your sash weighs 38 lbs, you can use a stamp option of 2965, which supports a window sash in the range of 35 through 39 lbs. Weigh your window sash if you want to be certain this will work.