Replacement window balances

Thanks for posting. I agree, this looks like either the S380-27 or S385-27 Channel Balance. The difference is the shoe depth, as shown below. Measure your old shoe's depth to see what matches best.

Comparison of the S378, S380 and S385 balance shoes.

You also have to choose a stamp option, which reflects the balance's strength. If there's no stamp on the metal channel, weigh the window sash these balances support. You can then match that exact weight with one of the weight ranges listed alongside each stamp option on the shop page. Let me know if you have further questions. 

A stamp of 26C often matches our 2630 option, but you can always weigh your sash and refer to our weight chart to verify.