channel balances, which channel do I need for replacement

Hello there. I am confident we can help, but that stamp is not an identifier; it just tells us the strength of the balance. To know what balance to pick, please send us clear photos of the nylon attachments at both ends. The combo of attachments will tell us what you need. 

Thanks for posting again. Looks like you have an S380-33 or S385-33 Channel Balance. Depending on the shoe depth, one of these may be what you need. See below. For a stamp option choose 3240.

Comparison of the S378, S380 and S385 balance shoes.

Glad to help, Steve. Let us know if you need anything else.