27" Series 770 Balance Product Code: S770-27

Hello there. The best thing to when there is an unusual stamp is to weigh the window sash the balances support. You can then match that exact weight with one of the weight ranges listed alongside each stamp option under the product description of every balance we carry. If you want to be absolutely sure you have a S770-27, be sure to confirm the length of the metal channel, to show us a picture of the clip at the bottom of the balance and how it attaches to the top of the window jamb--we'd be happy to take a look!