I can't find the lower rail width specification on any unit anywhere. I returned the one unit I bought because the lower rail (1 1/4" wide) didn't fit within my single hung window lower frame (1 1/16" wide).

I've tried calling the manufactures, but the the hold time is too long.

If the lower rail widths are not standard, what units will fit my application or how do find that information?

Thank you for your help.

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