SIX SORTER TRAYS:You also receive six trays for sorting puzzle pieces of different colors or shapes. So convenient easy to remove and store your progress. NON SLIP on the BOTTOM:The rubber base kept the mat in place and the puzzle pieces slide easily on the working surface. SMOOTH SURFACE and NO CREASES: It is sturdy, soft, flat. Our rubber puzzle mat is rolled up and packaged inside a long box for shipment, the surface of the rubber puzzle mat does not have any crease for your convenience. High quality rubber puzzle mat:Puzzle mat surface with size charts.The black provides good contrast for pieces.