Replacement Channel Balance Quesiton

Good question. Technically these stamps overlap at 36 pounds (2765 will cover a sash that weighs 33 through 36 pounds, and 2770 will support a sash weighing 36 through 39 pounds). However, if the window is anywhere over 36 pounds, even fractionally, I tend to just recommend the 2770 to be safe. Let me know if you have any further questions.