Counter balance

Hello, thank you for posting,

With this combination of attachments, you could have either an S380 or S385 channel balance. You’ll need to measure as shown below. The Series 380 has a 1" bottom attachment, and the Series 385 has a 1-3/32" attachment. 

Can you confirm that the length of the metal channel excluding the nylon attachments is 29" long? If so, the 28C stamp does not directly translate, but you should be able to use a 2830 stamp option. This spring strength can support a 16 to 23 lb window sash. I recommend weighing the window sash to confirm.

Comparison of the S380 and S385 balance shoes.

For the top sash guide, please compare the dimensions of 18-180 to confirm a match. Let me know if you have any additional questions!