Series 770 too short?

Thanks for posting. Sorry to hear your balances were the wrong length. Unfortunately, the wrong length will not work for your window. Stamp codes are not always indicative of the actual length, which is why it's best to check to be safe. Can you show us pictures of both ends of the balance, as well as the stamp code? Can you measure the length of the metal channel, not including any end attachments? Finally, I'd advise you weigh your window sash. We'll need that exact weight to confirm what stamp option you should select. 

As far as the charging tool, something like our 75-005 works fine with this which is why we recommend it. But to be honest, any kind of hook will do. Even needle nose pliers will suffice, if you can fit them in there. 

Thanks for getting back to me. OK, so this is more or less what we expected. It's an older version of the Series 770 where the stamp code was one number less than the length. So you'd need a S770-28. Now, 28F may be your stamp, as the older balance's stamp (in your case, 27F) often sync up, but there's no way to guarantee this without weighing your window sash. You can match that exact sash weight with one of the weight ranges listed alongside each stamp option on the product page.  

See our Return Policy here. Let me know if you have any other questions.