A quick learner from Columbus, OH says:
April 21, 2014
Home build in mid 80's. Attached is picture with stampings, 11600-17 by logo and J39 5#27 8 87 on opposite side. What part number can I use to buy replacements. Thank you.
Paul from SWISCO responded:
April 22, 2014
Please look at our 24-531 Andersen sash balance. This can replace balance boxes with the stamp 5#27.