Need replacement balance

Thanks for posting. It appears both attachments have 'wings' or side tabs, is that correct? If so, this is either an S385-30 or S380-30. The only difference between these two channel balances is the 'depth' of the bottom nylon shoe. See below. Measure your old balance's shoe depth to see what matches best.

Comparison of the S378, S380 and S385 balance shoes.

For the stamp option, that '38' should signify the window sash weighs 38 pounds. You can check this with a bathroom scale if you want to be safe. If so, choose stamp option 2965, which denotes a balance that can support a sash in the weight range of 35 through 39 pounds.

Sounds good, Brian. Let us know if you need anything else, and thanks again for reaching out.