Window channel balance

Hi Swisco, I was wondering if you can help me identify what kind of window balance I have. This is a single hung window. The balances sit at the top of the window (circled in red). Since the two cables are broken I was able to remove the balances with two screws and not have to fuss with the hooks attached to the pane.
The two balances sit in the white metal frame stacked on one another.
It looks like there's a spring and some pulleys that the string go through.
The cables on both balances are broken and at the end of the cable is a metal hook that hooks onto the pane that slides up and down.
I measured the balances and it looks to be 19" long.
Hopefully you sell these so I can order from you.
Thank you so much.