Window channel balance.

Thanks for writing in. The stamp of 28C translates to our stamp option 2830, while  28D to 2840. Please note that these stamps are not part identifiers--they are a rating system used to denote the strength of several different channel balances. If you're unsure of your channel balance's identity, send us a picture of the other nylon attachment. The style of both attachments determines the kind of balance you have. We'll do our best to assist you from there.

Thanks for clarifying! This is a huge help. Based on what I see here, you have either our S380-29 or S385-29, depending on the depth of the bottom shoe. That's the only difference between them. I recommend measuring your shoe and referring to our dimensions to confirm the best match. Note that we have other sizes, too, so if neither option matches then just let me know and we can pursue other possibilities.

One last note: if you have different stamped balances in the same window, then that's no good. The balances for a single window should be identical. You may need to weigh your sash to determine the proper option. We have a weight chart on every balance's store page that tells you precisely what kind of load each stamp option carries.

Comparison of the S378, S380 and S385 balance shoes.