Knobless Cylinders in 4 boxes

4 sets of 10 cylinders each, varying in height and/or diameter in each set. The knobless cylinders correspond in size to the cylinders in the cylinder blocks. Sets are coloured to match the box lid. They train the eye to perceive fine differences in dimension and to recognize differences and similarities. The cylinders have interrelationships in size that become apparent when the child works with more than one set. Spare pieces are included for the smallest piece in each set.