Double coil balance

Question

It has a #7 stamped on the spring.   Appears to be your 171 series but l'm not sure.  Right side as you're looking at the window.

Bob · Accepted Answer

This looks more like our 15-175 Pivot Shoe, which uses the Series 152 Coil Balances. A stamp of 7 on the coil itself would indicate you need an S152-7 7 lb spring. Let me know if you have further questions.