Tom from SWISCO responded:
March 17, 2020
Hello! That's actually a very peculiar stamp. I'm not sure why the manufacturer did that. It could be nothing, or it could be something extra special. I think the best way to confirm would be to remove the sash and place it on a scale, to get its weight. Two S370-29 balances with a 2810 stamp can carry sashes weighing 7 through 12 pounds. As long as your sash falls within that range, then the 2810 is what you want. If not, let me know and we'll find something better for your window. |