Looking for special fins of mcboard

[AsafR]

Im looking for long time fins of mcboard
Can anyone tell me how this fins s.n?
See photo.
If some of you can sell it...

[waikikikichan]

Look up " Red X fin systems ".

[AsafR]

Thanks
How can i know the size

[AsafR]

How can i know the size of it

[waikikikichan]

Whoever has any of this type of fins in stock won’t have much to choose from anyways. Just try to stay around the FCS M-5 size. Which is there go-to standard size.