These cylinders are designed for texturing hard foam. The cylinders are made out of a hard shock proof plastic. The structure in each cylinder is deep and the lines are sharp in order to get a perfect result even with less pressure.
To get a good imprint a round stick is used. By rolling the cylinder using the stick you apply only pressure where pressure is needed; The area where the cylinder touches the foam.
Using two discs on either side of the cylinder help you to align the cylinder while rolling it over the foam.