Flat-sawn Bracewood, produced with the finest tonewood fiber in the world. Procured from salvage sourced old-growth Sitka Spruce.
Next best to the ultimate split face flat sawn brace stock is this just flat sawn, without the split face. The reason is, when you resaw a flatsawn wide board into boards the result is a VG cut board. That is a Vertical grain cut brace. See the photo. I have penciled a rough example of the brace profile, and on the other board, penciled the VG cuts.
This product is sold by 1/2 boardfoot volume. .5 bdft = 72 cu inches[1 x 3 x 23.5 or equivalent]. We have been told by luthiers that 1/2 bdft should be enough for bracing a guitar.