Salvaged gym floor panel that was laid down on 2x4 sleepers. The 2 1/4", tongue & groove maple flooring is nailed to 2x4's. I believe the original thickness of the flooring was 5/4", but it's been sanded down over the years and now varies a bit from panel to panel. There's still a solid 3/4" from what I see, but some may still be 7/8"+. The dimensions listed are the largest rectangle that could be cut from the piece (if there's a not or angled cut, it's not included. Has been neatly squared up into panels by previous owner, who purchased it from us when it wasn't looking quite so nice. I heard they used a system of cables underneath and biscuits (from a biscuit jointer) to keep the panels tightly together, and it sounds like it worked well. Third use flooring!