I have a pair of single hung windows like the image on the left. They were put in by the developer of my 10-year-old condo and I do not know where they came from. There are no identifiers on the windows.
One window works fine allowing the window to slide up and down on two spring loaded window balancers.
On the broken window, the all-nylon shoe lock on the left balancer that holds a round insert (have this) is broken at the bottom (middle image).
On the right is an image of the same all-nylon shoe lock with round insert that works fine.
On the balancer is printed
