A contractor from Santa Rosa Beach, Florida says:
September 7, 2016
I have Alenco windows installed around 1984. The balance is stamped 2730. Does your product S371-28 work in the Alenco window. If so do I need the black top caps and no additional pieces? All the plastic pieces on the current windows have failed.
Tom from SWISCO responded:
September 9, 2016
Thanks for posting. I can't quite make out exactly what style your nylon caps are, but I don't think the Series 371 is what you want. Look at our Series 380 or Series 385 instead. The only difference between these two balances is the bottom shoe. You'll need to measure yours to confirm which is best.