Part number to order?

This will be a Series 385 or Series 380 channel balance, specifically S385-28 or S380-28. Measure the shoe to tell which one. The 1" shoe shown below belongs to S380-28, and the 1-3/32" shoe belongs to S385-28. You will want to consider the 2740 stamp option, which matches your old stamp and holds sashes between 19 and 26 pounds. You can verify the stamp by removing and weighing the sash.