Bob from SWISCO responded:
November 18, 2019
Thanks for writing in. This looks like a S377-28 to me. Your stamp code of I-27-4 likely conforms to our stamp option of 2740, which is for a window sash in the weight range of 19 through 26 lbs. If you are uncertain this is correct, weigh your window sash to be safe. Let us know if you have any other questions. |