need to order balance replacments

A contractor from mission texas says:
April 13, 2018
my 28 inch balance has stamp on it of[ 27 B] and my 16 inch has a stamp of[ 15 D ] what does that tell me.This house was built in 1982 and the windows are made by alenco.
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Casey from SWISCO responded:
April 13, 2018

Hi! Thanks so much for posting. 

The stamp that you are referring to on the side of your balance indicates the strength and sash weight category that you will select at checkout. This is sort of a final step in the process. 

To be able to determine the balances you have we will need to see some photos of the balance removed from the window. Please make sure to include the end nylon attachments in your photos. 

Get back to me if you have any questions! 
A contractor from mission texas says:
April 18, 2018
The balance i need is #351 but my 16 inch has a stamp of 15-d and your numbers are (1510,1520, 1530 ect.) and my 28 inch balance has a number of 27-b and your's are (2710,2720,2730 ect.). can you Please help me with this thanks.
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Casey from SWISCO responded:
April 19, 2018

Typically 15D would translate to 1540 and 27B to 2720. The weight ratings are listed in a chart on our product pages if you want to weigh your sash and double check. Let us know if you have any more questions or concerns. Thank you!
16" Series 351 Channel Balance
16" Series 351 Channel Balance
S351-16
$9.34
28" Series 351 Channel Balance
28" Series 351 Channel Balance
S351-28
$10.97
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