What window mechanism is this?

[andreadebiase]

Hello,
I am trying to rebuild/fix this window. I am familiar with the sash cord type but not this one with the metal wire. Does anyone know what is it called and do you think I may be able to find a replacement mechanism nowdays? this is a 1976 house.
thank you

 

[Snoonyb]

They are called sash balances and are available from most retail hrdw. outlets; sash balances for windows

 

[billshack]

this old house did a show all about this look it up

 

[andreadebiase]

They are called sash balances and are available from most retail hrdw. outlets; sash balances for windows

Thank you!