window pulley mechanism

Thanks for posting. This is called a channel balance. I'm sure we can help, but we'll need more information to identify the exact kind you have.

• First, can you tell us the length of the metal channel?
• Can you show us any stamp code on the metal channel?
• Can you remove an undamaged balance and show us any shoe, hook, or attachment at the bottom? This attachment should connect to the bottom corners of the window sash. 
• Can you show us how the balance attaches to the window track? Does it use a hook, or maybe a screw clip?

We should be able to narrow down your options from there. Many thanks.