Mast Fin Box

OK so fiber glass is fine, carbon is very sexy, but is balsa better.........!
Here's the proof

I honestly don't know how much more established manufacturers charge for a fiber glass fin, mast boxes but the above bespoke box when resined including generous labour cost would work out at under £20.00
As far as I'm aware balsa it's only slightly heavier but noticeably stronger than an equivalent in glass fibre.
Ooops time to get off the soap box.  Did I mention it's sustainable!