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 12″ x 17.25″. Great for use when learning about Math and numbers. Visualize where the numbers -20 to 120 fall on a number line. Practice math problems, counting and understanding when numbers go into the negatives.