This item is a single piece of 12 mm 1/2" x 12" x 30" Baltic Birch Plywood. The image above may show the various thicknesses that Woodcraft offers.This plywood is a functional grade material composed of birch from parts of Russia. The Baltic birch is graded as a B-BB, which means that one face, B, will be a whole face, no splices, have no patches (plugs that are used to cover defects) but may contain knot pattern or mineral streaks. The other face, BB, and the inner plies will contain patches and tight and not so tight knots. Baltic Birch Plywood is an excellent material for cabinet backs, drawer sides and bottoms, as well as jigs and fixtures and scroll saw work that will be painted. Please measure each piece carefully before starting any project. Plywood sizes are nominal. Dimensions are +/- 1/4" of size listed.