Block and tackle balance

Hello there. Do the nylon attachments on both ends of the balance lack 'wings', or side tabs? See the diagram below to get a sense of what I am talking about.

Diagram on how to choose between the 15-001, 15-002, 15-004, 15-005, and 15-029 channel balance shoes.

If they have wings, please send clear photos of both attachments so I can properly identify them. If they lack wings, then you need either an S351-17 or S390-17. The only difference between these two channel balances is the depth of the bottom nylon shoe, or its 'heel-to-toe' measurement. See the diagram below for reference. Compare both with your old balance to see what matches best. In either case, for a new stamp option choose 1620.

Comparison of the S351 and S390 balance shoes.