Which part do I order for a Unique 27-D-40?

A home owner from Naples, FL says:
My balance is stamped "Unique 27-D-40" but the chanel measures 28". Which replacement balance do I order, the 27" or the 28"?

Thank you, Ed Lary
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Donna from SWISCO responded:
Normally the Series 770 has a stamp number that begins with the balance length.

If you are unsure of the series you selected please post some detailed photos for us to look at.

If you are sure it is Series 770, please remove the window sash and place it on a scale. We need the weight of the window sash in pounds in order to determine the proper stamp option.
A home owner from Naples, FL says:
Hi Donna;
Thanks for the quick reply. No, I am not sure this is a Series 770. So, I'll take your advice and post a picture of the product with its dimensions, and then perhaps someone can advise which replacement part to order.
Thanks, Ed lary
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