window balance identification

A handy person from seattle says:
November 29, 2023
I need to replace 4 balances. The windows they live in are identical, but the balances in the frames have different markings. Otherwise they seem to be identical. One set of balances has the markings "28 4 EK Caldwell". The other set says " 28 4 EP Caldwell"

Both sets are 29" long. The metal hook is the same on all of them.

Thank you for your help!! My stupid landlord wont' fix our windows so I'm fixing them myself.
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Lauren from SWISCO responded:
November 30, 2023

Hello, thank you for posting,

With this combination of attachments, you could have either an S380 or S385 channel balance. You’ll need to measure as shown below. The Series 380 has a 1" bottom attachment, and the Series 385 has a 1-3/32" attachment. 

You will need a 29" balance with a 2840 stamp option that can support a 23 to 28 lb window sash. 

The letters following the 28 4 stamp can be disregarded. The spring strength is determined by the 28 4 only. Let me know if you have any additional questions! 

Comparison of the S380 and S385 balance shoes.
Comparison of the S380 and S385 balance shoes.
29" Series 380 Channel Balance
29" Series 380 Channel Balance
S380-29
$11.10
29" Series 385 Channel Balance
29" Series 385 Channel Balance
S385-29
$11.10
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