Balance BSI 2630(?)

Thanks for posting. I believe you have either an S351-27 or S390-27. The only difference between these two balances is the depth of the bottom nylon shoe, or the 'heel-to-toe' measurement. See the illustration below. I believe the shoe on your old balance is damaged, so if possible use an undamaged version and compare to the image below to see which option matches what you need. In either case for a new stamp option choose 2630.

Comparison of the S351 and S390 balance shoes.