Replacement Spiral Balances

A home owner from Oakland CA says:
I have three single-hung windows that will not stay up and I want to make sure I order the right replacement balances. The 306 series seems to visually match the ones I need to replace best, except that the tips are not red. I suspect they were white. All of the tips are broken and the only one that has any plastic remaining in it appears to be white. I may also have cleaned up white fragments when the windows originally broke (several months past), but definitely not red.

I can't find any numbers or other markings on the spiral balances, or on the windows for that matter (the previous owner probably installed Home Depot generics, judging from everything else in the home).

The window specs are as follows:
Two windows have 15 lb. sashes with 26" spiral balance tubes
One window has a 10 lb. sash with a 17" tube
User submitted a photo of window balances.
Profile picture of Tom
Tom from SWISCO responded:
Hello! Based on the weight of your sashes, our Red Tip option should work in both cases. That spring strength can comfortably hold the sash weights you gave us for both a 17" and 26" long balance.
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