Spiral window balances

A handy person from Manassas, VA says:
My spiral window balances are ~29" long, have a blue plastic end piece and my vinyl window (bottom half) weighs 27 lb. Which replacement spiral window balances do I need? Do you also sell white plastic tubes to cover the balances? Mine are covered with loose plastic sleeves that have cracked and broken. My windows do not have a plastic cover to hide the balances.

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Tom from SWISCO responded:
Thanks for posting! Can you please tell us what the diameter of your spiral balance tube is? Can you also confirm that the length of the tube is exactly 29"? Make sure to only measure the metal tube, not the plastic tip or spiral protrusion.
A handy person from Manassas, VA says:
The diameter of the spiral tube (without plastic cover) is 7/16" and the length is 28 & 7/16".
A customer submitted photo of their spiral balances.
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Tom from SWISCO responded:
Thank you for uploading your pictures! Please take a look at our S600-29 spiral balance with a blue tip. Please keep in mind that a blue tip for this type of balance can support a sash weight range of 12 through 31 lbs.

This information is based on 2 balances per sash. Balances are designed assuming friction in the jamb weather-strip will carry a portion of the sash weight. Suggested sash weights are approximate.
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