As designed it’s 10.5", but I wanted to use it as a trivet so I shrunk it down to 5.5 in the GFUI. Instead of using finished wood I coloured the layers with alcohol inks, and then sealed with Rustoleum Rippled Effect spray. I sealed the back and sides with tung oil.
I doubt it’s 300º resistant, but it does well enough against hot plates and bowls
It’s 3 layers of 1/8" - so just about 3/8" - and about the perfect depth. I’ve got a few that are around 1/2" thick but they’re closer to 8" across, probably much thicker than that would get awkward unless they were very large.