Brand is Rivco the only marking is stamped on the balancer is "24"

Hello! Looks like you need a new balance. It's tough to tell from a broken assembly but I believe this could be a match for our Series 751. Look it over and let me know if you agree, or if you had any questions!

The proper stamp will depend on the weight of the sash. We have a weight chart on each Series 751 store page that tells you precisely how much weight each option can carry. Once you get your sash weight, refer to that chart and pick accordingly.

As for the balances used for the top sash, they're not always the same. Sometimes they are but you can't bet on it. I always recommend checking. You don't want to guess.