Looking for window balance replacement parts

Question

Metal from end-to-end measures 28", but between the plastic ends measures 27"; 1/2" wide. I have 3 windows that need this part replaced.

Tom · Accepted Answer

This looks like a S395-28 channel balance, if the metal bar is 28" long. You'll need a 2740 stamp option due to your "27 4" balance marking. If you want to verify that information, you can weigh your window sash. Each stamp option carries a certain range of sash weights.