Balance Spring replacement

A handy person from Gilroy, CA says:
Markings: 26 4 FP Caldwell
Metal length measures 27"
Bottom plastic portion measures 1" depth (vs the 1 3/32 examples??)
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A handy person from Gilroy, CA says:
The size depth might have been 1 3/32 and is worn down.
Also, looks like a plastic tab in the last picture (with the broken cord) broke off.
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Bob from SWISCO responded:

Hello there. Check another balance if you're uncertain about the depth of the shoe. If it's greater than 1", but less than 1-3/32", then most likely it did indeed just wear down from age and the S385-27 is what you need (if it's 1-3/32" exactly, then of course, this is certainly the balance you need). If the balances are all 1" or slightly less though, then the S380-27 may be the better choice. See the image below for reference. In either case for a stamp option choose 2640. 

Comparison of the S380 and S385 balance shoes.
Comparison of the S380 and S385 balance shoes.
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