Channel Balances Needed

Thanks for posting. I agree, this is either a S380-30 or S385-30. The difference between these two balances Series is the depth of the bottom nylon shoe, or the 'heel-to-toe' measurement. For the Series 380, the shoe depth is 1"; the Series 385 is just slightly larger, at 1-3/32". See the bottom left of the picture below for reference. Measure the depth of your balance's shoe to determine which Series you need. 

You'll also need to choose a stamp option, which designates the calibrated strength of the balance. I can partly see the stamp in one of your photos (the code starting with '29'). The rest of the code should tell you what stamp option to select. If you are uncertain, or the stamp doesn't match any of our options, tell us what the stamp reads and also provide us the exact weight of the window sash that these balances support, and we can work it out for you.

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

You got it! The stamp 29-3 conforms to our rating of 2930, which means the balance is calibrated to support a window sash in the weight range of 16 through 23 pounds. Let me know if you have further questions, and thanks again for reaching out.