Window part

Thanks for writing in. This is called a window balance; specifically, this is a type called a channel balance. Balances are spring-loaded mechanisms that enable the opening and closing of a window. I believe this might be our Series 770 Channel Balance, but you'll need to go over all the specifications listed to confirm that it's a match--I cannot see the terminal clip at the end of the cord in your photos, so ensure that it matches. If you are indeed working with the Series 770, measure the length of the metal channel to determine the length you need. Look for a stamp code on the metal channel that indicates the stamp option you need. If there is no stamp or you are uncertain, weigh your window sash. You can match that exact weight with one of the weight ranges listed for each stamp option on the product page. Let us know what you think.