A contractor from Baltimore says:
March 22, 2016
I see the number 1031 on there. Please confirm before I order 20 something of them.
Paul from SWISCO responded:
March 24, 2016
Thanks for contacting us. A stamp of 1031 corresponds to our 24-1033 Andersen sash balance. Also, I recommend confirming that all of your windows are identical before you purchase that many balances, just in case.