Walnut and maple., it's an inch and a quarter thick, 12 1/2 inches wide and about 17 inches long. While it is an end grain cutting board I actually built it with kneading dough in mind, I don't intend to cut on this one, not for awhile anyway. Built it this weekend and baked some bread with it today. Which is why my mixer is covered in flour. I'm really happy with this one.
That older board I linked above? Here's what it looks like after a year of service. They do take scars especially from pizza wheels apparently, but there's no splintering, there's no bits fraying off into the food, and if it's too scarred up I can sand it smooth and keep using it. Compare that to a plastic board where I'm almost afraid to cut chicken on them twice.