Channel Balance for Milgard Window

Question

Window is Milgard, manufactured around 1984, aluminum frame, non-tilt.

Metal channel length is 21" long.

Not many markings on the part, only the "20 D" and what looks like "3.S.I." shown in the picture.

Tom · Accepted Answer

It looks like your bottom shoe is 1-1/8" deep, like the photo below. If so, choose S390-21. "20D" is an old code that we call "2040" nowadays.

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