2790 30 BSI 28" LONG METAL TO METAL, 1/2" WIDE

Thanks for your photos. Based on what I see here, you have either our S380-28 or S385-28, 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. You will also need to weigh your sash on a scale to verify the best stamp option; we have a chart on each balance's store page that will show you precisely how much each stamp supports.

Comparison of the S380 and S385 balance shoes.