Balance channel and say

Hello, thanks for posting! It looks like you could have either our Series 380 or Series 385. The difference between the Series 380 and the Series 385 lies in the depth of the shoe. Take a look at the picture below for more detail. Once you have determined this dimension you should be able to select the appropriate balance.

Comparison of the S380 and S385 balance shoes.

You will need to identify the stamp or imprint on the metal channel in order to determine which stamp option you require. If there is no stamp or imprint, you can weigh your window sash and refer to the chart on the product page. In regards to your top sash guide, review some of the options I've associated on the side. Compare their dimensions to your own hardware to see if any of them may be a match. 

Great! That tells you your stamp option. You will still need to measure the shoe on your existing balance to determine if it is our Series 380 or Series 385. Good luck with your repair, and let me know if you need any further assistance!