27 inch balance

You'll need either the S380-27 or the S385-27 to replace your balances. To determine the correct series, confirm the measurement for the depth of the bottom shoe, as shown below.

I believe the 2620 stamp should work for your repairs but you may want to double check that your sash weighs between 9 to 13lbs.

Comparison of the S378, S380 and S385 balance shoes.