Name of the metal strip that fits into the channel balance shoe?

Hi there! I need to replace the ~3 inch long metal strip that is embedded in the bottom rail of the window, and rests inside the channel balance shoe - it's the piece that pivots the shoe as the window folds out. Do you carry these for a Pennco single-hung?

Uploaded a picture of the metal piece (lying next to the screwdriver) and the label printed on the inside of my window.