Specification: Red & Blue Cubes: 2cm x 2cm x 2cm Yellow & Green Cubes: 2.5cm x 2.5cm x 2.5cm Description: Material: pine wood, can be made of EVA The number cubes offer a wide range of engaging, hands-on math applications and elementary math games as well. Grades PreK-8 1 red 2cm cube, numbered 0-5; 1 blue 2cm cube, numbered 5-10; 1 yellow 2.5cm cube, numbered 0 TENS - 5 TENS; 1 green 2.5cm cube, numbered 5 TENS - 10 TENS Safety Standard ASTM F963 & CPSIA2008 New Standard