It's a poster, it's a placemat, it's both. Smart Poly® material has been designed for the classroom and home. The material is strong, durable, water resistant, and does not need lamination. Heavy duty surface for fun and colorful learnings. Write-on/wipe-off surface for use with dry erase or water based markers and washable crayons. Measures 13" x 9.5" . Use in the classroom, home or office to draw out and visualize grids. Use for math, art, and any other skills. 24x16 block space, 384 spaces.