Smart Poly material has been designed for charts in the classroom and home. The charts are strong, durable, water proof, and do not need lamination. The write-on/wipe-off surface is designed for dry erase or water based markers and washable crayons. Smart Poly Chart measures 13" x 19" with a heavy duty, glossy surface, .45mm. Grommet hole for easy hanging. Two pieces, no assembly required. Turn the wheel to tell and learn about time.