I need 2 replace channel balance non tilt single hung window

Thanks for writing in. Unfortunately I can't tell you if the S350-27 is the right channel balance for you because that stamp only tells us the strength of the balance, not its identity. Many of our non-tilt channel balances have that same code, 2640, imprinted on them. It's the attachments on either end of the metal channel that determine a channel balance's identity. Can you send us photos of those attachments, or fittings? That will help us narrow down precisely what you need. 

Thanks for the photos, they help a great deal. Your balances have a winged top and a winged bottom. So, with that said, it looks like you have either the S380-27 with a 1" shoe or the S385-27 with a 1-3/32" shoe.

To determine which series is needed for your window, look over the dimensions from the diagram below to confirm the depth of your bottom shoe. Let me know if it does not match either measurement.

You'll need to select the 2640 stamp.

Comparison of the S378, S380 and S385 balance shoes.

Thank you for the kind feedback. I'm happy to hear that you were satisfied with our service and that you got your order placed. 

Please feel free to reach out with any other hardware repair projects you may have.

Have a great day!