Replacement Balancer

This appears to be a Series 770 balance with a rivet in the second-to-top hole, is that correct? We can build these balances for you but they'll have to be custom made due to their unique design. The rivet would use an S-Clip like the 19-029 or 19-030, sold separately, to attach to the window jamb. Can you confirm the length of the metal channel is 22"? And is there a stamp code on the metal channel you can show us? Finally, how many balances do you need? From there we'll get this started for you. 

Thanks for getting back to me. This confirms you need an S770-22 with a rivet put in the second-to-top hole so you can use an S-Clip like the 19-029 or 19-030, sold separately. Two points here before we proceed:

• (2) is our minimum quantity for custom orders. Note that we always recommend replacing both balances in a window anyway; if one breaks, the other usually isn't far behind. 
• The stamp code 21C is a little unusual for a 22" balance of this type, though we do see it from time to time. This may translate to our S770-22 with a stamp option of 22C. The stamp option of 22C supports a window sash in the weight range of 16 through 21 lbs. I highly advise you obtain the exact wight of your window sash to ensure it falls within this weight range before proceeding with your order. As all custom orders are non-refundable, it's always best to be thorough. 
• If your balance does not fall in that weight range, do not go ahead with the order. Let me know instead what the exact weight is, and I'll adjust the custom order specifications accordingly. 

If the sash weight does fall into that weight range, I think we're good to go. I am sending you an email with a custom link to order (2) of these balances. Let me know if you have any further questions prior to making your order.