Channel Block & Tackle window balance

Home Owner from
I need to get 2 of these. Length is 34" and width is 1/2". Can't find any stamp or marking, so hope the pictures will help.
Window is broken so I could not take pictures of it installed. 
Thanks!
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Bob
Bob from SWISCO
SWISCO
Expert

Thanks for posting. Is the metal channel 34" long, not including the nylon attachments at both ends? If so, this is likely either an S380-34 or S385-24. The only difference between these two channel balance is the 'depth' of the bottom nylon shoe, or the 'heel-to-toe' measurement. See the diagram below for reference.

Comparison of the S378, S380 and S385 balance shoes.
Comparison of the S378, S380 and S385 balance shoes.

You then have to choose a stamp option, which designates the strength of the balance. The stamp on your old balance that would indicate this seems hard to read. I advise you weigh the window sash the balances support. You can use that exact weight to choose the right stamp option. 

Home Owner from CA
Thanks for your help! The heel-toe measurement is 1", and the metal channel is 34", so the S300-34 should work. Can you let me know where I can find the "stamp"? I don't see it anywhere on the metal channel?
Bob
Bob from SWISCO
SWISCO
Expert

It looks like you can see the stamp in IMG_2658 that you sent in your first post--it's on the metal channel close to the end of the bottom nylon shoe. I can't totally see it in the photo. It might be 3340 but that's just a guess and not a confirmation. See what you can find. If not, weighing the window sash will be your best bet. And yes, if the shoe depth is 1", then it's an S380-34. Let me know if you have further questions.

Home Owner from CA
It's 3340, so I'll order S380-34 (with option 3340). Thank you very much for your help! Appreciate it. 
Bob
Bob from SWISCO
SWISCO
Expert

My pleasure! Let us know if you need anything else, and many thanks for contacting us.

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