identify replacement channel balance

I am sure we can help, but that stamp is not a model number; it simply tells us the calibration of the balance. Can you remove the balance and show us pictures of the nylon fittings on both ends of the metal channel? That would help narrow things down. Many thanks. 

Thanks. is the metal channel, not including the nylon fittings on both ends, 27" long? If so, seems like you need either a S380-27 or S385-27. The only difference between these two balances is the depth of the bottom nylon shoe, or the 'heel-to-toe' measurement, so compare both with your old hardware to see what matches best. See the diagram below for details. For a new stamp option, choose 2650.

Comparison of the S380 and S385 balance shoes.

That cord is part of the spring system in the channel balance. Our channel balances come fully assembled with the fittings and cord so that they're ready to install to the window out-of-the-box. Let me know if you have further questions. 

Let me clarify. The stamp option designates the weight range the balances are calibrated to support. Your old balances had a stamp code that included 26-5. This indicates to me you need new balances that use our equivalent stamp option of 2650, which can support a window sash in the weight range of 26 through 30 pounds. You always want the window sash's exact weight to fall within the range designated by the stamp option; otherwise the window will have difficulty opening or closing. You can always weigh your window sash to confirm this. Let me know if you have further questions. 

Thanks for the kind words! Always nice to hear a good success story. Let us know whenever you need anything else, and many thanks for your business.