Balance replacement needed
Hello there. That stamp code of 33-4 translates to our balances' stamp option of 3340, which denotes a balance that can support a window sash in the weight range of 23 through 28 pounds. Note that many of our channel balances have this as a stamp option, and Unfortunately this stamp does not tell us what kind of balance you need. To know that we would need to see pictures of the nylon attachments on both ends of the balance, with the balance removed from the window for a clear view. That's the only reliable way to identify a balance replacement.
Those are perfect, thanks. I think you have either an S380-34 or S385-24 Channel Balance. The only difference between these two balances is the nylon shoe depth. See below. Measure your old balance's shoe to see what matches best. For a stamp option choose 3340.
