I've used the Andersen chart to identify my window size as 23 15/16" x 40 7/16"
#3846
Narroline
Paul from SWISCO responded:
March 24, 2016
Based on that sash size, I think you might want to consider our 24-1133. If you would like us to confirm, however, I will need to know what each stamp printed on the metal box reads.