Please help me identify the right channel balance to order

Question

I need to order 2 different types of channel balances:

Type 1:
31 inches long
Numbers: 3020 AC "B.S.I."

Type 2:
35 inches long
Numbers: 3430 "B.S.I."

Can you please let me know as soon as possible what I need to order?
I submitted a similar information request some time ago but didn't see a response.

Thank you for your assistance.
Be well, Carsten

Bob · Accepted Answer

Hi Carsten. Those stamp codes only tell us the calibration of the balances, not their identity. This looks like either a Series 351 or Series 390 Channel Balance. The only difference between these two balances is the depth of the bottom nylon shoe, so compare both with your old hardware to see what matches best. The image below depicts that difference.

Comparison of the S351 and S390 balance shoes.

Assuming both length balances have the same fittings, for the 31" balances, choose a stamp option of 3020; for the 35" balances, use a stamp option of 3430.

Comparison of the S351 and S390 balance shoes.

Assuming both length balances have the same fittings, for the 31" balances, choose a stamp option of 3020; for the 35" balances, use a stamp option of 3430.