Searching for 5/8" 30 4 ht cmc 4 channel block

Thanks for posting. I am afraid that stamp just tells us the strength of the balance, not its identity. To know its identity we need a picture of the top fitting as well. From there we should be able to narrow this down for you. 

Perfect, thank you! That's exactly what I needed to see. Based on what you show here, you have either our S380-31 or S385-31, depending on the depth of the bottom shoe. That's the only difference between them. I recommend measuring your shoe and referring to our dimensions to confirm the best match.

Comparison of the S378, S380 and S385 balance shoes.