Looking for 2 new balancers

A handy person from California says:
The balancers I have are marked 2640. I've been trying to match them up to your options but having a tough time matching the end closest to the spring(see picture) the other end near the pulleys seems to match up to options you have available. The balancers are 1/2 wide. Please let me know if you have anything that would match.
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Bob from SWISCO responded:

Thanks for writing in. Balances are actually identified by the style of the nylon fittings on both ends of the metal channel; the stamp code just refers to the calibration of the spring inside the balance. We can identify this balance for you, but we'll need to see the bottom nylon fitting as well. From there, we'll narrow down the right kind or Series you need. Many thanks.

A handy person from California says:
Here are more pictures of the nylon fittings on both ends. Let me know if this is enough or there is something else you need to see specifically about the ends.
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Bob from SWISCO responded:

Thanks for replying back with more photos. Your balance looks close to both our Series 380-27 and S385-27. The difference between these two balances lie within the measurement of the bottom balance shoe. The depth of the Series 380 is 1" and for the Series 385 is 1-3/32". You will need to measure the depth of your bottom balance shoe, like in the diagram below, to determine which balance is the best match for you. Whichever one chosen will go with the 2640 option. 

Alternate view of 15-004
Alternate view of 15-004
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