Marked 33. 5. BSI

Thanks for your photos. Based on what I see here, you have either our S380-34 or S385-34, 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 S380 and S385 balance shoes.

It should also be noted that your top sash guide is either damaged or missing, which is what caused your balance to shoot up in the track like it has. That will need to be replaced, as well, though I cannot make a recommendation without seeing a clear picture of the original. For now, you can see our full selection here. The video below will also offer insight on what I'm talking about.