
Regarding window channel balance parts and model

Look at your bottom balance shoe. We'd like for you to measure it. If the bottom balance depth is 1", our S380-28 channel balance would be the choice for you. If it measures 1-3/32", our S385-28 channel balance would be the one to choose. Either one you decide on would have the 2750 option based on your stamping of "27 5". Get back to us and let us know how you made out.
You don't necessarily want a balance that is too light or too strong for your window. Think of it like Goldilocks' porridge: it has to be just right. You may want to weigh your sash on a scale and then refer to the chart we show on the S385-28 store page to confirm the best match.