1st Quality Aircraft Grade Birch Plywood. Good 2 sides. 

All Micro-Mark miniature lumber is clear, kiln-dried No.1 grade. Wood sheets are micro-sanded both sides. Siding and moldings are precision milled and require no sanding. For cutting sheet stock into narrow strips, we recommend Table Saw #50304 for thicknesses up to 1/4 inch. For thicker sizes and plywood use the MicroLux Tilting Arbor Table Saw, #80463.