2 Caldwell channel balances

A quick learner from USA says:
I need to replace 2 Caldwell channel balances. The balance is 27" long and 1/2" wide, inside depth is ~9/16". See photos attached. My main concern with the replacements is the width of the hook that attaches to the sash. The hole is my sash is 6mm and the width on the Caldwell hook is 6mm. I had a local company order me 2 replacement balances last year. Everything was fine except for the width of the hook which was 7mm. I tried unsuccessfully to remedy this by decreasing the size of the hook. Please let me know if you need more information about my balance. Please send me information on which channel balance to order.TIA
User submitted photos of a window balance.
Profile picture of Tom
Tom from SWISCO responded:
Hey, thanks for posting. I've narrowed this down to two possible channel balance Series: either our Series 380 or our Series 385 balances.

Now, as you can see, there is only one difference between these two Series, and that is their bottom shoe. The Series 380 uses the 15-005 while the Series 385 uses the 15-004. I can't quite tell what you have based on your pictures, though. Please carefully compare their dimensions to your own hardware and see which is a better match.
15-004 and 15-005
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