These smooth painted wooden buttons feel nice in the hand and the size differences are quite apparent. Sort buttons by color, then line up color sets in size-graded rows. For a simple activity, start with three or four colors, then gradually add more. Seven colors, each in three sizes (20 mm, 30 mm, 40 mm); 21 pieces in all. Packed in the fun-to-open clear plastic Clip Lid box. The largest button is about 1½" dia. Ages 3 and up.