window balances

Thanks for your post! Your balance is a discontinued Arrow balance. It can be replaced with the Series 770 Channel Balance, made with a 1/2" wide channel.

It appears you balances measure 28" in length, so you'll need the S770-28 for your repairs. To select the stamp for your balance, you'll need to weigh the window sash. 

There is a chart below the product description of the balance that lists the weight range each stamp can support.