I measured dimensions per your specs and the 15 inch series 390 is what I would require. The only thing I'm not sure of is the sash weight range. The stamp on the side says 14E U.S.B. Please advise.
Thank You, Dan
Tom from SWISCO responded:
September 8, 2020
A stamp of 14E usually corresponds to our 1450 option. If you aren't sure, you can always weigh your sash on a scale and refer to the chart shown on the S390-15 store page.